Re-add support for Symbol objects via JSSymbol

[j-f1]

This re-adds the functionality removed by #180.

(I accidentally pushed this change to main first, sorry about that!)

The Reflect namespace is mainly intended for use with Proxy objects, with each function on that namespace matching the signature of the corresponding proxy trap. For most use cases, normal access is preferable.

The test failure was occurring because Reflect.* functions check that their parameter is really an object. While this is the case for objects, symbols aren’t objects; the [] syntax automatically converts to an object where necessary.

[github-actions[bot]]

Time Change: +603.75ms (7%) 🔍

Total Time: 8,585.75ms

Test name	Duration	Change
Serialization/Write JavaScript number directly	203.5ms	+34.25ms (16%)	⚠️
Serialization/Write JavaScript string directly	197ms	+22.25ms (11%)	⚠️
Serialization/Swift Int to JavaScript	2,670ms	+250.25ms (9%)	🔍
Serialization/Swift String to JavaScript	2,666.25ms	+207.25ms (7%)	🔍

ℹ️ View Unchanged

| Test name | Duration | Change | | :--- | :---: | :---: | | Object heap/Increment and decrement RC | 2,849ms | +89.75ms (3%) |

_{performance-action}

[kateinoigakukun]

For the record: https://tc39.es/ecma262/#sec-reflect.get

28.1.5 Reflect.get ( target, propertyKey [ , receiver ] ) When the get function is called with arguments target, propertyKey, and receiver, the following steps are taken:

1. If Type(target) is not Object, throw a TypeError exception.