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/PrivatesInSecondPressCompletion.kt

@@ -0,0 +1,13 @@
+import java.io.File
+
+class MyFile : File("file") {
+    private val privateField = 0
+}
+
+fun foo(f: MyFile) {
+    f.<caret>
+}
+
+// INVOCATION_COUNT: 2
+// EXIST: privateField
+// ABSENT: prefixLength