invert boolean: invert assignment if used as expression (IDEA-152284)

java/java-tests/testData/refactoring/invertBoolean/assignment.java

@@ -0,0 +1,10 @@
+class C {
+  boolean f<caret>oo() {
+    return false;
+  }
+
+  void bar() {
+    boolean a, b;
+    a = b = foo();
+  }
+}