Created module idea-test-framework and moved classes needed for idea tests there

Moved tests for completion and their test data into module idea-completion

idea/idea-completion/testData/basic/common/RecieverMembersFromExtFun.kt

@@ -0,0 +1,11 @@
+class A {
+    public fun foo(): Int = 1
+    public val bar: Int = 1
+}
+
+fun A.ext() {
+    <caret>
+}
+
+// EXIST: foo
+// EXIST: bar