commit 1676cf0b4a4bad9c37df2f2becc695dc0785d507
Author: Ryan Aslett (Mixologic) <ryan@association.drupal.org>
Date:   Fri May 25 12:46:51 2018 -0700

    Sets javascript testing to be concurrency of 15 once we no longer have phantomjs tests in core

diff --git a/core/drupalci.yml b/core/drupalci.yml
index b658e475b8..b539d562af 100644
--- a/core/drupalci.yml
+++ b/core/drupalci.yml
@@ -47,7 +47,7 @@ build:
       # Functional JavaScript tests require a concurrency of 1 because there is
       # only one instance of PhantomJS on the testbot machine.
       run_tests.javascript:
-        concurrency: 1
+        concurrency: 15
         types: 'PHPUnit-FunctionalJavascript'
         testgroups: '--all'
         suppress-deprecations: false