Large StandardCompiler (AST JSON) output cannot be parsed by jsoncpp

Found by ossfuzz (12705).

```
contract C { function f() public pure { ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(1);
}
}
```

The negation operator results in a large nested object in the AST JSON output, which makes jsoncpp to run out of stack depth parsing:
```
libc++abi.dylib: terminating with uncaught exception of type Json::RuntimeError: Exceeded stackLimit in readValue().
Abort trap: 6
```

This happens in solfuzz only where the compilation output is parsed into JSON.

Start in solfuzz where compilation output is parsed into JSON, and reproduce the provided contract with the long negation expression. Trace the AST JSON handling with jsoncpp and verify that this input no longer fails with the Exceeded stackLimit error.

Written by the indexing model from the issue text.