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/smartMultiFile/Inheritors/JavaInheritors.java

@@ -0,0 +1,16 @@
+import p2.KotlinTrait
+
+public abstract class JavaInheritor1 implements KotlinTrait {
+}
+
+public class JavaInheritor2 extends JavaInheritor1 {
+    public JavaInheritor2() {
+    }
+
+    public JavaInheritor2(int p) {
+    }
+}
+
+// not visible - it's package local
+class JavaInheritor3 extends KotlinTrait {}
+