Added second quickfix on conflicting extension to mark it hidden and deprecated

idea/testData/quickfix/migration/conflictingExtension/wrongExplicitThis2.kt

@@ -0,0 +1,9 @@
+// "Delete redundant extension property" "false"
+
+class C : Thread() {
+    var Thread.<caret>priority: Int
+        get() = getPriority()
+        set(value) {
+            this@C.setPriority(value)
+        }
+}