Memory leak for certain bytecode

The following byte code triggers a memory leak:

```c
0x60, 0x60, 0x60, 0x53, 0x53
```

I'm currently using this code to run the EVM:

```cpp
1 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
2 {
3 struct evm_instance* instance = evmjit_create();
4 if (EVM_ABI_VERSION != instance->abi_version)
5 {
6 return 1;
7 }
8 struct evm_uint256be code_hash;
9 memset(&code_hash, 0, sizeof(code_hash));
10 MD5(data, size, (unsigned char*)&code_hash);
11 uint8_t const input[] = "Hello World!";
12 struct evm_uint256be value = {{1, 0,}};
13 struct evm_address addr = {{0, 1, 2,}};
14 int64_t gas = 2000;
15 struct evm_message msg = {addr, addr, value, input, 0,
16 code_hash, gas, 0};
17 struct evm_context ctx = {&ctx_fn_table};
18 struct evm_result result =
19 instance->execute(instance, &ctx, EVM_HOMESTEAD, &msg, data, size);
20 return 0;
21 }
```

Start by reproducing the report with the bytecode sequence 0x60, 0x60, 0x60, 0x53, 0x53 using the shown LLVMFuzzerTestOneInput harness. Trace the lifecycle around evmjit_create() and instance->execute(); done means the input no longer produces a memory leak.

Written by the indexing model from the issue text.