Issue #2983781 by Lendude: Update drupalci.yml concurrency comment to match...

Issue #2983781 by Lendude: Update drupalci.yml concurrency comment to match the new reality of FunctionalJavascript

core/drupalci.yml

@@ -44,8 +44,6 @@ build:
         testgroups: '--all'
         suppress-deprecations: false
         halt-on-fail: false
-      # Functional JavaScript tests require a concurrency of 1 because there is
-      # only one instance of PhantomJS on the testbot machine.
       run_tests.javascript:
         concurrency: 15
         types: 'PHPUnit-FunctionalJavascript'