make static: process anonymous class usages (EA-21912 - assert: MakeClassStaticProcessor.changeExternalUsage)

java/java-tests/testData/refactoring/makeClassStatic/DefaultConstructorAnonymousClass_after.java

@@ -0,0 +1,16 @@
+public class A {
+  static class B {
+      public B() {
+      }
+  }
+}
+
+class C {
+  void foo() {
+    new A().new B() {
+      public String toString() {
+        return super.toString();
+      }
+    }.toString();
+  }
+}