Bug 1285936 - Make import-*-globals rules into errors for automation. r=me

MozReview-Commit-ID: IrjMIH3fl5K

testing/mochitest/browser.eslintrc

@@ -1,8 +1,8 @@
 // Parent config file for all browser-chrome files.
 {
   "rules": {
-    "mozilla/import-headjs-globals": 1,
-    "mozilla/import-browserjs-globals": 1,
+    "mozilla/import-headjs-globals": 2,
+    "mozilla/import-browserjs-globals": 2,
   },
 
   "env": {