Introduce module 'reflection', move KFunctionN to it

Metadata for KFunction classes is now longer serialized along with built-in
classes. This effectively means that it's no longer possible to find KFunction
classes via dependency on built-ins. There should be a kotlin-runtime library
in the specified classpath for reflection types to be resolvable.

A lot of tests were moved and changed, because tests on callable references
require stdlib in classpath from now on

compiler/testData/codegen/boxWithStdlib/callableReference/function/local/extensionWithClosure.kt

@@ -0,0 +1,11 @@
+class A
+
+fun box(): String {
+    var result = "Fail"
+
+    fun A.ext() { result = "OK" }
+
+    val f = A::ext
+    A().f()
+    return result
+}