Bug 1391532 - Preserve the precision of a timestamp when converting it to string. r=bkelly

testing/web-platform/tests/service-workers/service-worker/resources/update-max-aged-worker-imported-script.py

@@ -6,7 +6,7 @@ def main(request, response):
                ('Last-Modified', time.strftime("%a, %d %b %Y %H:%M:%S GMT", time.gmtime()))]
 
     body = '''
-        const importTime = {time};
+        const importTime = {time:8f};
     '''.format(time=time.time())
 
     return headers, body

testing/web-platform/tests/service-workers/service-worker/resources/update-max-aged-worker.py

@@ -9,7 +9,7 @@ def main(request, response):
     test = request.GET['test']
 
     body = '''
-        const mainTime = {time};
+        const mainTime = {time:8f};
         const testName = {test};
         importScripts('update-max-aged-worker-imported-script.py');