[SwiftBuild] PackageToJS plugin fails to generate correct js initializer code

[sliemeobn]

for a browser / WASI use case this will result in an error like: "wasi_snapshot_preview1": module is not an object or function

because triple detection is based on the build output path:

JavaScriptKit/Plugins/PackageToJS/Sources/PackageToJS.swift

Lines 72 to 81 in e53155d

	static func deriveBuildConfiguration(wasmProductArtifact: URL) -> (configuration: String, triple: String) {
	// e.g. path/to/.build/wasm32-unknown-wasi/debug/Basic.wasm -> ("debug", "wasm32-unknown-wasi")
	// First, resolve symlink to get the actual path as SwiftPM 6.0 and earlier returns unresolved
	// symlink path for product artifact.
	let wasmProductArtifact = wasmProductArtifact.resolvingSymlinksInPath()
	let buildConfiguration = wasmProductArtifact.deletingLastPathComponent().lastPathComponent
	let triple = wasmProductArtifact.deletingLastPathComponent().deletingLastPathComponent().lastPathComponent
	return (buildConfiguration, triple)
	}

and swift-build produces different out paths like this: .build/out/Products/Release-webassembly-wasm32/App.wasm

template variables like IS_WASI are no longer correctly derived

JavaScriptKit/Plugins/PackageToJS/Sources/PackageToJS.swift

Line 813 in e53155d

"IS_WASI": triple.hasPrefix("wasm32-unknown-wasi"),