Effectively revert the trait-based manifest change

[kateinoigakukun]

Unfortunately, SwiftPM does not respect the enabled traits for validating the usage of unsafeFlags. After f9b3973, we are seeing the following validation error when a package depends on JavaScriptKit package with .package(url: "...", from:) form.

error: 'basic': the target 'JavaScriptKit' in product 'JavaScriptKit' contains unsafe build flags

We need to temporarily revert the trait change

[github-actions]

Time Change: -99ms (1%)

Total Time: 9,599ms

Test name	Duration	Change
Serialization/JavaScript function call through Wasm import with int	20ms	-1ms (5%)	✅

View Unchanged

Test name	Duration	Change
Serialization/JavaScript function call through Wasm import	22ms	-0ms
Serialization/JavaScript function call from Swift	126ms	-2ms (1%)
Serialization/Swift Int to JavaScript with assignment	324ms	-1ms
Serialization/Swift Int to JavaScript with call	963ms	-9ms (0%)
Serialization/JavaScript Number to Swift Int	260ms	-5ms (1%)
Serialization/Swift String to JavaScript with assignment	405ms	-0ms
Serialization/Swift String to JavaScript with call	1,055ms	0ms
Serialization/JavaScript String to Swift String	3,598ms	-61ms (1%)
Object heap/Increment and decrement RC	2,793ms	-18ms (0%)

View Baselines

Test name	Duration
Serialization/Call JavaScript function directly	8ms
Serialization/Assign JavaScript number directly	9ms
Serialization/Call with JavaScript number directly	5ms
Serialization/Write JavaScript string directly	7ms
Serialization/Call with JavaScript string directly	5ms