Remove amd64-generic and x86-generic freon

After the changes to default freon for amd64-generic and x86-generic
landed, we no longer need freon builders for these.

This CL removes the related configurations from cbuildbot.

Also update the binhost_test to correctly handle the case where a PFQ
builder is deleted from the waterfall so it doesn't fail in this case.

BUG=chromium:532719
TEST=unittest

Change-Id: I8277036f4588a1c42f9fea5ef2df19b4330eca87
Reviewed-on: https://chromium-review.googlesource.com/320463
Commit-Ready: Haixia Shi <hshi@chromium.org>
Tested-by: Haixia Shi <hshi@chromium.org>
Reviewed-by: Haixia Shi <hshi@chromium.org>
3 files changed