[Wasm] Support WASI target in K2

- Support WASI mode in CLI and test infrastructure
- Add external declaration checker
- Split Fir diagnostic lists into Base, JS and WASI

#KT-56849 Fixed

wasm/wasm.frontend/src/org/jetbrains/kotlin/wasm/resolve/diagnostics/WasmWasiExternalDeclarationChecker.kt

@@ -16,7 +16,6 @@ import org.jetbrains.kotlin.resolve.checkers.DeclarationChecker
 import org.jetbrains.kotlin.resolve.checkers.DeclarationCheckerContext
 import org.jetbrains.kotlin.resolve.descriptorUtil.isEffectivelyExternal
 
-// TODO: Implement in K2: KT-56849
 object WasmWasiExternalDeclarationChecker : DeclarationChecker {
     override fun check(declaration: KtDeclaration, descriptor: DeclarationDescriptor, context: DeclarationCheckerContext) {
         if (descriptor !is MemberDescriptor) return