tests: Correct testcase in script_tests.json for large number OP_EQUAL
tests: Correct testcase in script_tests.json for large number OP_EQUAL

Fix a test case that was passing correctly by accident, but not testing
the right thing. Reported by helo on IRC.

chaincoin/chaincoin,chaincoin/chaincoin,chaincoin/chaincoin,chaincoin/chaincoin,chaincoin/chaincoin,chaincoin/chaincoin