llvm_tools: add a simple cherrypick script

Given a SHA, this script will cherrypick the CL from LLVM, add it to the
appropriate filesdir, and update PATCHES.json with an appropriate
comment.

No testing is included, since the code is pretty straightline, and it's
expected to be used interactively. In other words, if it breaks,
*shrug*.

BUG=chromium:1057428
TEST=Ran on a few test-cases.

Change-Id: I8cb361bb29ec239316847a781a1edfd7941c7551
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2095772
Tested-by: George Burgess <gbiv@chromium.org>
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>
2 files changed