invert if: do not skip returns as they may contain valuable info (IDEA-61892)

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/advHighlighting/OperatorApplicability.java

@@ -44,7 +44,7 @@ public class a {
     ia[~i | (i+=(!b?2:i))] -= i + 3.3;
     
     // Object += String
-    o += o + "string";
+    <error descr="Operator '+' cannot be applied to 'java.lang.Object','java.lang.String'">o += o + "string"</error>;
 
     return 0;
   }

java/java-tests/testData/codeInsight/invertIfCondition/afterDoNotRemoveReturn.java

@@ -0,0 +1,10 @@
+// "Invert If Condition" "true"
+class Test {
+    public static int create() {
+        if (true) {
+            return;
+        }
+        return "s";
+
+    }
+}

java/java-tests/testData/codeInsight/invertIfCondition/beforeDoNotRemoveReturn.java

@@ -0,0 +1,9 @@
+// "Invert If Condition" "true"
+class Test {
+    public static int create() {
+        if (!tr<caret>ue) {
+            return "s";
+        }
+
+    }
+}