Initial support for KT-7090 Completion for callable references

#KT-7090 Fixed

idea/idea-completion/testData/basic/common/callableReference/SyntheticExtensions2.kt

@@ -0,0 +1,9 @@
+import java.io.File
+
+class MyFile : File("") {
+    val v = ::<caret>
+}
+
+// EXIST_JAVA_ONLY: { itemText: "freeSpace", tailText: " (from getFreeSpace())", attributes: "" }
+// EXIST_JAVA_ONLY: { itemText: "isFile", tailText: " (from isFile())", attributes: "" }
+// ABSENT: { itemText: "isFile", tailText: "()" }