check for contract code ending in an empty push pre fork 10 (#1159)

* check for contract code ending in an empty push pre fork 10

* fix: wrong case usage

* fixing panic on len == 0, going to -1

* remove hard coded 0x60 for push1 check

---------

Co-authored-by: Arthur Abeilice <afa7789@gmail.com>

core/vm/evm_zkevm.go

@@ -271,6 +271,14 @@ func (evm *EVM) call_zkevm(typ OpCode, caller ContractRef, addr libcommon.Addres
 	var code []byte
 	if !isPrecompile {
 		code = evm.intraBlockState.GetCode(addr)
+
+		// zk - up to fork 10 we cannot handle a contract code that ends with just a push and nothing to push to the stack
+		// so check for this scenario
+		if !evm.chainConfig.IsForkID10(evm.Context.BlockNumber) {
+			if len(code) > 0 && code[len(code)-1] == byte(PUSH1) {
+				return nil, gas, ErrInvalidCode
+			}
+		}
 	}
 
 	snapshot := evm.intraBlockState.Snapshot()