invert boolean: leave expressions with unused return value untouched (IDEA-56568 )

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

@@ -0,0 +1,9 @@
+class C {
+  boolean f<caret>oo() {
+    return false;
+  }
+
+  void bar() {
+    foo();
+  }
+}

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

@@ -0,0 +1,9 @@
+class C {
+  boolean fooInverted() {
+    return true;
+  }
+
+  void bar() {
+    fooInverted();
+  }
+}