pgo_tools: update the merge script to work with recipe and buildbucket

Since the scheduled builder for toolchain team has been migrated to
recipe and also we are launching builders manually with `bb` command, this
CL updates the PGO merging and uploading script to make it work with the
change.

BUG=chromium:1076624
TEST=Tested with 3 different modes and exception raising.

Change-Id: I993d1cbbf7ba66502e6bc6b8d82bd97cfda67b1e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2225841
Tested-by: Zhizhou Yang <zhizhouy@google.com>
Reviewed-by: George Burgess <gbiv@chromium.org>
1 file changed