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

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https://hg.mozilla.org/integration/gaia-central/rev/35970bcd80cb
Author: evanxd <itoyxd@gmail.com>
Desc: Merge pull request #16241 from evanxd/bug-972215

Bug 972215 - Update the doc for running a specific marionette test.

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https://hg.mozilla.org/integration/gaia-central/rev/7a0d6419a308
Author: Evan Xd <itoyxd@gmail.com>
Desc: Bug 972215 - Do documentation for invoking some specific marionette tests. r=eragon
Bumping manifests a=b2g-bump