Extension properties in class: don't put receiver on stack for GETFIELD/PUTFIELD instruction

#KT-3031 Fixed

compiler/testData/codegen/extensionProperties/inClassWithSetter.kt

@@ -0,0 +1,16 @@
+class Test {
+  var Int.foo: String = "fail"
+    set(str: String) {
+        $foo = str
+    }
+
+  fun test(): String {
+      val i = 1
+      i.foo = "OK"
+      return i.foo
+  }
+}
+
+fun box(): String {
+   return Test().test()
+}