JVM IR: change generation scheme of property $delegate methods

Generate $delegate method as instance method in
PropertyReferenceDelegationLowering, and remove dispatch receiver later
in MakePropertyDelegateMethodsStatic. The method needs to be static to
be non-overridable (see delegateMethodIsNonOverridable.kt), and public
to be accessible in reflection.

Otherwise we generated incorrect IR where a static function accessed an
instance field of the containing class, which failed in multiple places
including LocalDeclarationsLowering.

 #KT-48350 Fixed

compiler/testData/codegen/box/delegatedProperty/referenceEnclosingClassFieldInReceiver2.kt

@@ -0,0 +1,25 @@
+// WITH_RUNTIME
+
+interface I {
+    var z: String
+}
+
+class X {
+    var p: String = "Fail"
+}
+
+class A {
+    val x = X()
+
+    inner class Y : I {
+        override var z: String by x::p
+    }
+
+    val y = Y()
+}
+
+fun box(): String {
+    val a = A()
+    a.y.z = "OK"
+    return a.y.z
+}