Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/7da96a5a6ec9
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #18585 from bebef1987/delete_1

Bug 1000062 - Delete some more redundant tests

========

https://hg.mozilla.org/integration/gaia-central/rev/64783de3f0ee
Author: Bebe <bebe@mozilla.ro>
Desc: Bug 1000062 - Delete some more redundant tests
Bumping manifests a=b2g-bump