Add env variable to disable qa dev-shm

Allow local qa runs to disable dev-shm in chrome as well

qa/qa/runtime/browser.rb

@@ -99,7 +99,7 @@ module QA
             end
 
             # Disable /dev/shm use in CI. See https://gitlab.com/gitlab-org/gitlab/issues/4252
-            capabilities['goog:chromeOptions'][:args] << 'disable-dev-shm-usage' if QA::Runtime::Env.running_in_ci?
+            capabilities['goog:chromeOptions'][:args] << 'disable-dev-shm-usage' if QA::Runtime::Env.disable_dev_shm?
 
             # Specify the user-agent to allow challenges to be bypassed
             # See https://gitlab.com/gitlab-com/gl-infra/infrastructure/-/issues/11938

qa/qa/runtime/env.rb

@@ -80,6 +80,11 @@ module QA
         enabled?(ENV['CHROME_REUSE_PROFILE'], default: false)
       end
 
+      # Disable /dev/shm use in CI. See https://gitlab.com/gitlab-org/gitlab/issues/4252
+      def disable_dev_shm?
+        running_in_ci? || enabled?(ENV['CHROME_DISABLE_DEV_SHM'], default: false)
+      end
+
       def accept_insecure_certs?
         enabled?(ENV['ACCEPT_INSECURE_CERTS'])
       end