This calls the action that archives test262 in gn. In gn
we can't specify an action output outside the product
directory. This works around it with an extra action
stamp file in the product directory, while the archive
remains in the test directory.

We don't want to generate the archive in the product
directory, as some legacy archiving scripts might include
it and it's too large. It should only be included in the
swarming tasks that are going to use it for testing.

BUG=chromium:474921

Review-Url: https://codereview.chromium.org/2034713005
Cr-Commit-Position: refs/heads/master@{#36731}