Added tests

idea/testData/completion/smart/ImmediateExtensionMembers.kt

@@ -0,0 +1,11 @@
+fun String.extFunForString(): Int = 0
+fun Any.extFunForAny(): Int = 0
+
+class C {
+    fun foo(): Int {
+        return "".<caret>
+    }
+}
+
+// EXIST: { itemText: "extFunForString", attributes: "bold" }
+// EXIST: { itemText: "extFunForAny", attributes: "" }