Merge "repo_pull: Automatically extract gerrit instance from `repo manifest`" am: 9160fbc06f am: 4b1b426db2 am: b4d79d9975

Original change: https://android-review.googlesource.com/c/platform/development/+/1353903

Change-Id: I5e4fdd94330ed4cfebc3b83170b2c4967d2ec9e9