Add test for DER-encoding edge case

The fix to NegateSignatureS caused a test which had been failing
in IsValidSignatureEncoding to then fail in IsLowDERSignature.
Add new test so the original check remains exercised.

src/test/data/script_invalid.json

@@ -695,6 +695,12 @@
     "DERSIG",
     "BIP66 example 11, with DERSIG"
 ],
+[
+    "0x48 0x304402203e4516da7253cf068effec6b95c41221c0cf3a8e6ccb8cbf1725b562e9afde2c022054e1c258c2981cdfba5df1f46661fb6541c44f77ca0092f3600331abfffb12510101",
+    "0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG",
+    "DERSIG",
+    "P2PK with multi-byte hashtype, with DERSIG"
+],
 [
     "0x48 0x304502203e4516da7253cf068effec6b95c41221c0cf3a8e6ccb8cbf1725b562e9afde2c022100ab1e3da73d67e32045a20e0b999e049978ea8d6ee5480d485fcf2ce0d03b2ef001",
     "0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG",

src/test/data/script_valid.json

@@ -813,6 +813,12 @@
     "DERSIG",
     "BIP66 example 12, with DERSIG"
 ],
+[
+    "0x48 0x304402203e4516da7253cf068effec6b95c41221c0cf3a8e6ccb8cbf1725b562e9afde2c022054e1c258c2981cdfba5df1f46661fb6541c44f77ca0092f3600331abfffb12510101",
+    "0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG",
+    "",
+    "P2PK with multi-byte hashtype, without DERSIG"
+],
 [
     "0x48 0x304502203e4516da7253cf068effec6b95c41221c0cf3a8e6ccb8cbf1725b562e9afde2c022100ab1e3da73d67e32045a20e0b999e049978ea8d6ee5480d485fcf2ce0d03b2ef001",
     "0x21 0x03363d90d447b00c9c99ceac05b6262ee053441c7e55552ffe526bad8f83ff4640 CHECKSIG",

src/test/script_tests.cpp

@@ -476,6 +476,12 @@ BOOST_AUTO_TEST_CASE(script_build)
     good.push_back(TestBuilder(CScript() << OP_2 << ToByteVector(keys.pubkey1C) << ToByteVector(keys.pubkey2C) << OP_2 << OP_CHECKMULTISIG << OP_NOT,
                                "BIP66 example 12, with DERSIG", SCRIPT_VERIFY_DERSIG
                               ).Num(0).PushSig(keys.key1, SIGHASH_ALL, 33, 32).EditPush(1, "45022100", "440220").Num(0));
+    good.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey2C) << OP_CHECKSIG,
+                               "P2PK with multi-byte hashtype, without DERSIG", 0
+                              ).PushSig(keys.key2, SIGHASH_ALL).EditPush(70, "01", "0101"));
+    bad.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey2C) << OP_CHECKSIG,
+                               "P2PK with multi-byte hashtype, with DERSIG", SCRIPT_VERIFY_DERSIG
+                              ).PushSig(keys.key2, SIGHASH_ALL).EditPush(70, "01", "0101"));
 
     good.push_back(TestBuilder(CScript() << ToByteVector(keys.pubkey2C) << OP_CHECKSIG,
                                "P2PK with high S but no LOW_S", 0