Bug 1196320 - ensure --appname is included in mochitest's ./mach command help, r=ahal

--HG--
extra : commitid : 7dLnFjQ6aCp
extra : rebase_source : ef3d2b65426b04acf1542206487d6611fd2bd5b0
extra : amend_source : 7b8d363f0cffb762d64e9254205ae25c092ed521

testing/mochitest/mochitest_options.py

@@ -78,7 +78,6 @@ class MochitestArguments(ArgumentContainer):
           "help": "Override the default binary used to run tests with the path provided, e.g "
                   "/usr/bin/firefox. If you have run ./mach package beforehand, you can "
                   "specify 'dist' to run tests against the distribution bundle's binary.",
-          "suppress": build_obj is not None,
           }],
         [["--utility-path"],
          {"dest": "utilityPath",