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/extensionToLocalClass.kt

@@ -0,0 +1,5 @@
+fun box(): String {
+    class A
+    fun A.foo() = "OK"
+    return (::A)().(A::foo)()
+}