Added browser specific Cucumber tags

Paired with Kartik Mistry.

Bug: 62477
Change-Id: I52ec4b73eb8d2e36d30985cf224a9339eed88cb1

tests/browser/features/manage_translator_sandbox.feature

@@ -1,4 +1,4 @@
-@login @sandbox.translatewiki.net
+@firefox @login @sandbox.translatewiki.net
 Feature: Manage translator sandbox
 
   As a translation administrator,

tests/browser/features/special_translate.feature

@@ -1,3 +1,4 @@
+@firefox @meta.wikimedia.org
 Feature: Special:Translate
 
   This page is the primary web translation interface for users.
@@ -7,17 +8,17 @@ Feature: Special:Translate
   https://commons.wikimedia.org/wiki/File:Translate-workflow-spec.pdf?page=10
   describes how it is meant to look and behave.
 
-  @meta.wikimedia.org @sandbox.translatewiki.net
+  @sandbox.translatewiki.net
   Scenario: Workflow selector not being visible
     Given I am translating a message group which doesn't have workflow states
     Then I should not see a workflow state
 
-  @custom-setup-needed @meta.wikimedia.org
+  @custom-setup-needed
   Scenario: Workflow selector being visible
     Given I am translating a message group which has workflow states
     Then I should see a workflow state
 
-  @custom-setup-needed @meta.wikimedia.org
+  @custom-setup-needed
   Scenario: Workflow selector being clickable
     Given I am translating a message group which has workflow states
     When I click the workflow state

tests/browser/features/translation_stash.feature

@@ -1,4 +1,4 @@
-@login @sandbox.translatewiki.net @stash
+@firefox @login @sandbox.translatewiki.net @stash
 Feature: Translation stash
 
   As a new translator, I can make translations in sandbox mode so that a translation administrator