Issue #3681: fixed NPE in RightCurly when do has no curlies

src/main/java/com/puppycrawl/tools/checkstyle/checks/blocks/RightCurlyCheck.java

@@ -370,7 +370,9 @@ public class RightCurlyCheck extends AbstractCheck {
             case TokenTypes.LITERAL_DO:
                 nextToken = ast.findFirstToken(TokenTypes.DO_WHILE);
                 lcurly = ast.findFirstToken(TokenTypes.SLIST);
-                rcurly = lcurly.getLastChild();
+                if (lcurly != null) {
+                    rcurly = lcurly.getLastChild();
+                }
                 break;
             default:
                 // ATTENTION! We have default here, but we expect case TokenTypes.METHOD_DEF,

src/test/resources/com/puppycrawl/tools/checkstyle/checks/blocks/InputRightCurlyDoWhile.java

@@ -90,5 +90,9 @@ public class InputRightCurlyDoWhile {
     public void foo9() {
         do {} while (true);
     }
+
+    public void foo10() {
+        do ; while (true);
+    }
 }