better error handling

Author: rbri

src/main/java/org/htmlunit/javascript/JavaScriptEngine.java

@@ -987,6 +987,9 @@ private void doProcessPostponedActions() {
                     }
                 }
             }
+            catch (final RuntimeException e) {
+                throw e;
+            }
             catch (final Exception e) {
                 throw JavaScriptEngine.throwAsScriptRuntimeEx(e);
             }