JS backend: tests for reflection support

js/js.translator/testData/callableReference/function/cases/extensionFromTopLevel.kt

@@ -0,0 +1,25 @@
+// This test was adapted from compiler/testData/codegen/boxWithStdlib/callableReference/function/.
+package foo
+
+fun <T> run(arg1: A, arg2: T, funRef:A.(T) -> T): T {
+    return arg1.funRef(arg2)
+}
+
+class A {
+    var xx: Int = 100
+}
+
+fun A.bar(x: Int): Int {
+    this.xx = this.xx * 2
+    return x
+}
+
+fun box(): Boolean {
+    val funRef = A::bar
+    val obj = A()
+    var result = obj.(funRef)(25)
+    if (result != 25 || obj.xx != 200) return false
+
+    result = run(A(), 25, funRef)
+    return result == 25 && obj.xx == 200
+}