Bug 1400683 - Add 'coverage' field to mozinfo to disable tests on linux64-jsdcov. r=jmaher

This patch makes it possible to disable mochitest-devtools tests on linux64-jsdcov through the 'coverage' flag.

MozReview-Commit-ID: 1gkgbFo19MZ

--HG--
extra : rebase_source : 9c6d311cb467e4424d42848e1caf024f9702b8cd

testing/mochitest/runtests.py

@@ -2408,6 +2408,9 @@ toolbar#nav-bar {
             options.e10s = False
         mozinfo.update({"e10s": options.e10s})  # for test manifest parsing.
 
+        if options.jscov_dir_prefix is not None:
+            mozinfo.update({'coverage': True})
+
         self.setTestRoot(options)
 
         # Despite our efforts to clean up servers started by this script, in practice