Create From Usage: Move "Create function"-related tests to separate directory

idea/testData/quickfix/createFromUsage/createFunction/call/beforeThisInExtension.kt

@@ -0,0 +1,7 @@
+// "Create function 'foo' from usage" "true"
+
+class A<T>(val n: T)
+
+fun <U> A<U>.test(): A<Int> {
+    return this.<caret>foo(2, "2")
+}