Add additional script edge condition tests.

This commit adds several tests to the script_invalid.json data which
exercise some edge conditions that are not currently being tested.

These are mainly being added to cover several cases a branch coverage
analysis of btcd showed are not already being covered, but given more
tests of edge conditions are always a good thing, I'm contributing
them upstream.

src/test/data/script_invalid.json

@@ -141,6 +141,8 @@
 ["2 2 0 IF LSHIFT ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "LSHIFT disabled"],
 ["2 2 0 IF RSHIFT ELSE 1 ENDIF", "NOP", "P2SH,STRICTENC", "RSHIFT disabled"],
 
+["", "EQUAL NOT", "P2SH,STRICTENC", "EQUAL must error when there are no stack items"],
+["0", "EQUAL NOT", "P2SH,STRICTENC", "EQUAL must error when there are not 2 stack items"],
 ["0 1","EQUAL", "P2SH,STRICTENC"],
 ["1 1 ADD", "0 EQUAL", "P2SH,STRICTENC"],
 ["11 1 ADD 12 SUB", "11 EQUAL", "P2SH,STRICTENC"],
@@ -368,6 +370,16 @@
 ["NOP", "HASH160 1", "P2SH,STRICTENC"],
 ["NOP", "HASH256 1", "P2SH,STRICTENC"],
 
+["Increase CHECKSIG and CHECKMULTISIG negative test coverage"],
+["", "CHECKSIG NOT", "STRICTENC", "CHECKSIG must error when there are no stack items"],
+["0", "CHECKSIG NOT", "STRICTENC", "CHECKSIG must error when there are not 2 stack items"],
+["", "CHECKMULTISIG NOT", "STRICTENC", "CHECKMULTISIG must error when there are no stack items"],
+["", "-1 CHECKMULTISIG NOT", "STRICTENC", "CHECKMULTISIG must error when the specified number of pubkeys is negative"],
+["", "1 CHECKMULTISIG NOT", "STRICTENC", "CHECKMULTISIG must error when there are not enough pubkeys on the stack"],
+["", "-1 0 CHECKMULTISIG NOT", "STRICTENC", "CHECKMULTISIG must error when the specified number of signatures is negative"],
+["", "1 'pk1' 1 CHECKMULTISIG NOT", "STRICTENC", "CHECKMULTISIG must error when there are not enough signatures on the stack"],
+["", "'dummy' 'sig1' 1 'pk1' 1 CHECKMULTISIG IF 1 ENDIF", "", "CHECKMULTISIG must push false to stack when signature is invalid when NOT in strict enc mode"],
+
 ["",
 "0 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG 0 0 CHECKMULTISIG",
 "P2SH,STRICTENC",
@@ -779,6 +791,12 @@
     "SIGPUSHONLY",
     "P2SH(P2PK) with non-push scriptSig"
 ],
+[
+    "0 0x47 0x304402205451ce65ad844dbb978b8bdedf5082e33b43cae8279c30f2c74d9e9ee49a94f802203fe95a7ccf74da7a232ee523ef4a53cb4d14bdd16289680cdb97a63819b8f42f01 0x46 0x304402205451ce65ad844dbb978b8bdedf5082e33b43cae8279c30f2c74d9e9ee49a94f802203fe95a7ccf74da7a232ee523ef4a53cb4d14bdd16289680cdb97a63819b8f42f",
+    "2 0x21 0x02a673638cb9587cb68ea08dbef685c6f2d2a751a8b3c6f2a7e9a4999e6e4bfaf5 0x21 0x02a673638cb9587cb68ea08dbef685c6f2d2a751a8b3c6f2a7e9a4999e6e4bfaf5 0x21 0x02a673638cb9587cb68ea08dbef685c6f2d2a751a8b3c6f2a7e9a4999e6e4bfaf5 3 CHECKMULTISIG",
+    "P2SH,STRICTENC",
+    "2-of-3 with one valid and one invalid signature due to parse error, nSigs > validSigs"
+],
 [
     "11 0x47 0x304402200a5c6163f07b8d3b013c4d1d6dba25e780b39658d79ba37af7057a3b7f15ffa102201fd9b4eaa9943f734928b99a83592c2e7bf342ea2680f6a2bb705167966b742001",
     "0x41 0x0479be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8 CHECKSIG",