Move some benchmarks from MotoG4 to Mokey (#149567)

On Linux hosts, there are currently 5 mokey's in staging and 7 in prod.
On Linux hosts, there is currently 1 MotoG4 in staging and 11 in prod.

This PR shifts the ~5 tests that have been running on mokey's for awhile
now from staging to prod, and shifts about half of the MotoG4 benchmarks
from MotoG4's in prod to mokey's in staging.

Following this change, we can disconnect half of the Linux/MotoG4's in
the prod pool and replace them with mokey's in the prod pool.

Part of flutter/flutter#148085

Author: zanderso