Optimize object property access for StaticString keys

[github-actions[bot]]

Time Change: -1,039ms (12%) 👏

Total Time: 8,116ms

Test name	Duration	Change
Serialization/JavaScript function call through Wasm import	19ms	-3ms (16%)	👏
Serialization/JavaScript function call through Wasm import with int	14ms	-2ms (14%)	👏
Object heap/Increment and decrement RC	1,545ms	-1,036ms (67%)	🏆

View Unchanged

| Test name | Duration | Change | | :--- | :---: | :---: | | Serialization/JavaScript function call from Swift | 96ms | -3ms (2%) | | Serialization/Swift Int to JavaScript with assignment | 322ms | -3ms (0%) | | Serialization/Swift Int to JavaScript with call | 926ms | +7ms (0%) | | Serialization/JavaScript Number to Swift Int | 293ms | -4ms (1%) | | Serialization/Swift String to JavaScript with assignment | 390ms | +4ms (1%) | | Serialization/Swift String to JavaScript with call | 967ms | -14ms (1%) | | Serialization/JavaScript String to Swift String | 3,531ms | +15ms (0%) |

View Baselines

| Test name | Duration | | :--- | :---: | | Serialization/Call JavaScript function directly | 3ms | | Serialization/Assign JavaScript number directly | 2ms | | Serialization/Call with JavaScript number directly | 3ms | | Serialization/Write JavaScript string directly | 2ms | | Serialization/Call with JavaScript string directly | 2ms |