Make sure <url>s are being serialized according to spec

LayoutTests/resources/js-test.js

 // js-test now supports lazily printing test results which dumps all test
 // results once at the end of the test instead of building them up. To enable
 // this option, call setPrintTestResultsLazily() before running any tests.
 var _lazyTestResults; // Set by setPrintTestResultsLazily().
 
 // svg/dynamic-updates tests set enablePixelTesting=true, as we want to dump text + pixel results
 if (self.testRunner) {
     if (self.enablePixelTesting)
         testRunner.dumpAsTextWithPixelResults();
     else
@@ skipping 245 matching lines @@
      _exception = e;
   }
   var _bv = eval(_b);
 
   if (_exception)
     testFailed(_a + " should be " + _bv + ". Threw exception " + _exception);
   else if (isResultCorrect(_av, _bv) || (typeof opt_tolerance == 'number' && typeof _av == 'number' && Math.abs(_av - _bv) <= opt_tolerance)) {
     if (!quiet) {
         testPassed(_a + " is " + _b);
     }
-  } else if (typeof(_av) == typeof(_bv))
+  } else if (typeof(_av) == typeof(_bv)){
     testFailed(_a + " should be " + _bv + ". Was " + stringify(_av) + ".");
+  }
   else
     testFailed(_a + " should be " + _bv + " (of type " + typeof _bv + "). Was " + _av + " (of type " + typeof _av + ").");
 }
 
 // Execute condition every 5 milliseconds until it succeed or failureTime is reached.
 // completionHandler is executed on success, failureHandler is executed on timeout.
 function _waitForCondition(condition, failureTime, completionHandler, failureHandler)
 {
   if (condition()) {
     completionHandler();
@@ skipping 612 matching lines @@
     testPassed = function(msg) {
         workerPort.postMessage('PASS:' + msg);
     };
     finishJSTest = function() {
         workerPort.postMessage('DONE:');
     };
     debug = function(msg) {
         workerPort.postMessage(msg);
     };
 }