Optimize object property access for StaticString keys

[kateinoigakukun]

No description provided.

[github-actions]

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