Add JSTypedArray.init(buffer:) initializer

[kateinoigakukun]

Without this initializer, the only way to create a TypedArray with a UnsafeBufferPointer was to convert it to an Array first and then create a new TypedArray from it.

[github-actions]

Time Change: -34ms (0%)

Total Time: 9,527ms

Test name	Duration	Change
Serialization/JavaScript function call through Wasm import	23ms	-3ms (11%)	👏

View Unchanged

Test name	Duration	Change
Serialization/JavaScript function call through Wasm import with int	23ms	+1ms
Serialization/JavaScript function call from Swift	125ms	+4ms (3%)
Serialization/Swift Int to JavaScript with assignment	327ms	+5ms (1%)
Serialization/Swift Int to JavaScript with call	955ms	+3ms (0%)
Serialization/JavaScript Number to Swift Int	262ms	+2ms (0%)
Serialization/Swift String to JavaScript with assignment	407ms	+3ms (0%)
Serialization/Swift String to JavaScript with call	1,034ms	-3ms (0%)
Serialization/JavaScript String to Swift String	3,550ms	-11ms (0%)
Object heap/Increment and decrement RC	2,788ms	-35ms (1%)

View Baselines

Test name	Duration
Serialization/Call JavaScript function directly	7ms
Serialization/Assign JavaScript number directly	8ms
Serialization/Call with JavaScript number directly	6ms
Serialization/Write JavaScript string directly	5ms
Serialization/Call with JavaScript string directly	6ms