[JS] Support multimodule IC tests with K2

Includes supporting klib file generation.

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/K2JsIrCompiler.kt

@@ -555,6 +555,7 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
                 firOutputs = analyzedOutput.output,
                 fir2IrActualizedResult = fir2IrActualizedResult,
                 outputKlibPath = outputKlibPath,
+                nopack = arguments.irProduceKlibDir,
                 messageCollector = messageCollector,
                 diagnosticsReporter = diagnosticsReporter,
                 jsOutputName = arguments.irPerModuleOutputName,

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/klib/compilerPipeline.kt

@@ -302,6 +302,7 @@ fun serializeFirKlib(
     firOutputs: List<ModuleCompilerAnalyzedOutput>,
     fir2IrActualizedResult: Fir2IrActualizedResult,
     outputKlibPath: String,
+    nopack: Boolean,
     messageCollector: MessageCollector,
     diagnosticsReporter: BaseDiagnosticsCollector,
     jsOutputName: String?,
@@ -320,7 +321,7 @@ fun serializeFirKlib(
         fir2IrActualizedResult.irModuleFragment,
         expectDescriptorToSymbol = mutableMapOf(),
         cleanFiles = icData ?: emptyList(),
-        nopack = true,
+        nopack = nopack,
         perFile = false,
         containsErrorCode = messageCollector.hasErrors() || diagnosticsReporter.hasErrors,
         abiVersion = KotlinAbiVersion.CURRENT, // TODO get from test file data