toolchain-utils: Add a script to do post-process on Chrome orderfile.

This script takes an orderfile that contains symbols ordered by C3,
and an nm result of the Chrome binary and perform post-processing,
including add markers to begin and end, and insert all the builtin
functions in the Chrome binary.

The script is used by chromite when generating orderfile.

The CL is intended to be landed at the same time of crrev.com/c/1583077.
BUG=chromium:950627
TEST=Unittest and tryjob together with crrev.com/c/1583077

Change-Id: Ib8e85efdcf0dca053febd65c4e1c8350bf410437
Reviewed-on: https://chromium-review.googlesource.com/1605142
Tested-by: Tiancong Wang <tcwang@google.com>
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: George Burgess <gbiv@chromium.org>
2 files changed