java completion: qualify calls to outer class methods when needed (IDEA-144816, IDEA-151237)

java/java-tests/testData/codeInsight/completion/normal/InstanceMethodFromOuterClass.java

@@ -0,0 +1,10 @@
+class A {
+  void foo(int x){}
+  class Inner {
+    void foo(){}
+
+    void test() {
+      fo<caret>
+    }
+  }
+}