Equality comparison for bound callable references takes into account bound receiver.

Fixed KT-14939: use expected receiver type when generating receiver code in get/set methods for bound property references.
Otherwise we have VerifyError for bound receiver 'null' of type 'Nothing?', which is mapped to 'java.lang.Void'.

TODO: proper equality comparison for property accessors ('x::prop.getter', 'x::prop.setter').

compiler/testData/codegen/box/callableReference/bound/nullReceiver.kt

@@ -0,0 +1,9 @@
+// TODO: investigate should it be ran for JS or not
+// IGNORE_BACKEND: JS
+
+// See https://youtrack.jetbrains.com/issue/KT-14939
+
+val String?.ok: String
+    get() = "OK"
+
+fun box() = (null::ok).get()