[infra] Make the Android_Framework bot run on demand

This causes it to never get triggered automatically, so it will only run
as a try job or when force-triggered.

Caveat: if the job is defined on non-master branches, it will still
trigger for those branches.

Bug: skia:
Change-Id: Idff63bd22536b21ec21eb4b569cc392642297d7b
Reviewed-on: https://skia-review.googlesource.com/123923
Reviewed-by: Ravi Mistry <rmistry@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
2 files changed