infra/go: Begin removing gotools.test/assert

This dependency does not play nicely with chrome_infra.
In preparation of (at least a partial) move, remove dependencies on
this package.

BUG=None
TEST=go test ./...

Change-Id: I535acefcffbe7347ff5250c1ce8a9862593f4def
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/infra/go/+/2728284
Reviewed-by: Sean Abraham <[email protected]>
Commit-Queue: Jack Neus <[email protected]>
Tested-by: Jack Neus <[email protected]>
Auto-Submit: Jack Neus <[email protected]>
4 files changed