Use different versions for pgo_generate and pgo_use.
Use different versions for pgo_generate and pgo_use.

Right now, we upload both pgo_use and pgo_generate images to the same
location, which causes trouble for caching logic inside HWTest. Update
this logic to add a pgo_generate suffix to version numbers for the
pgo_generate builder so that caching logic won't reuse the wrong image,
and so that reimaging logic can determine that the devices need to be
updated.

BUG=chromium:235597
TEST=Remote trybot with and without HWTest (lumpy-pgo-release,
     x86-alex-pgo-release, x86-alex-release-group,
     x86-zgb-release-group, mario-paladin)
TEST=All unit tests.
STATUS=Fixed

Change-Id: I5f934eb0b809945999cd1266c6b2a23f7d5ebe2f
Reviewed-on: https://gerrit.chromium.org/gerrit/49235
Reviewed-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>
Commit-Queue: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>

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