Use GerritPatch directly rather than fake patch class.
Use GerritPatch directly rather than fake patch class.

Mox objects are not easily pickleable, making it difficult to pass them
around between parallel processes. Switch to using GerritPatch directly
so that we can start having parallel behavior in tests.

BUG=chromium:334032
TEST=All unit tests.
TEST=--buildbot --debug paladin run.

Change-Id: I9dd612ace5395b89c4447c7e3ef00a9724d7a26f
Reviewed-on: https://chromium-review.googlesource.com/184462
Reviewed-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Commit-Queue: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>

chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite