Fix literal parsing in legacy AST for older Solidity versions

[ep0chzer0]

Summary

• Fixes parsing failure for fixed-size array declarations in Solidity 0.4.x contracts
• Some older Solidity versions store numeric literals with embedded quotes in legacy AST

Root Cause

In Solidity versions like 0.4.23, the legacy AST format stores numeric literal values with embedded double-quotes. For example, the array declaration uint256[12] has its length stored as '"12"' (with quote characters) instead of just '12'.

This caused ValueError: invalid literal for int() with base 10: '"12"' when computing storage layout.

Fix

Strip surrounding double-quotes from literal values when parsing legacy AST (lines 447-450 in expression_parsing.py).

if isinstance(value, str) and value.startswith('"') and value.endswith('"'):
    value = value[1:-1]

Test Case

pragma solidity 0.4.23;
contract C {
    uint256[12] private c = [4,8,12,16,20,24,28,32,36,40,44,48];
}

This should now parse without errors.

Fixes #2215