Avoid running the Marionette specific tests against FirefoxDriver

Author: davehunt

py/build.desc

@@ -10,7 +10,7 @@
 
 py_test(
   name = "firefox_test",
-  ff_specific_tests = [ "test/selenium/webdriver/firefox/*_tests.py" ],
+  ff_specific_tests = [ "test/selenium/webdriver/firefox/ff_*_tests.py" ],
   deps = [ ":test_ff" ],
   resources = [
     { "//javascript/firefox-driver:webdriver_prefs" : "selenium/webdriver/firefox/webdriver_prefs.json" },