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/enumExtendsTrait.kt

@@ -0,0 +1,11 @@
+fun box(): String {
+    trait Named {
+        fun name(): String
+    }
+    
+    enum class E : Named {
+        OK
+    }
+
+    return E.OK.(Named::name)()
+}