[infra] Use the gclient provided browsers on all builders

This should land after the corresponding recipe change landed:
https://dart-review.googlesource.com/c/recipes/+/153120

#42417

Change-Id: I0eb569e3b0c9c1d401c7924b5e021b259e6638a4
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/153206
Commit-Queue: Alexander Thomas <[email protected]>
Reviewed-by: William Hesse <[email protected]>

Author: athomas