[JS IR] Fix kotlin.test framework

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/TestGenerator.kt

@@ -56,7 +56,7 @@ class TestGenerator(val context: JsIrBackendContext) : FileLoweringPass {
     ): FunctionWithBody {
         val body = JsIrBuilder.buildBlockBody(emptyList())
 
-        val function = JsIrBuilder.buildFunction("$name test fun", context.irBuiltIns.unitType, parentFunction)
+        val function = JsIrBuilder.buildFunction("$name test fun", context.irBuiltIns.anyNType, parentFunction)
         function.body = body
 
         val parentBody = parentFunction.body as IrBlockBody

libraries/kotlin.test/js/src/main/kotlin/kotlin/test/TestApi.kt

@@ -53,7 +53,7 @@ internal fun suite(name: String, ignored: Boolean, suiteFn: () -> Unit) {
 }
 
 @JsName("test")
-internal fun test(name: String, ignored: Boolean, testFn: () -> Unit) {
+internal fun test(name: String, ignored: Boolean, testFn: () -> Any?) {
     adapter().test(name, ignored, testFn)
 }