clang upload script: Skip presubmits on upload.

- The CLs created by this script are mininmal and none of the changes
  done by the script affect presubmits.

- It's a tiny bit faster.

- It allows running the script in a checkout that didn't run
  `gclient sync`; as-is a presubmit tries to read
  build/config/gclient_args.gni which doesn't exist then.

TBR=hans

Bug: none
Change-Id: I5801810e9f04f3436e84230cd6559f68b0a77451
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1758910Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688546}

tools/clang/scripts/upload_revision.py

@@ -84,7 +84,7 @@ def main():
   Git(["commit", "-m", "Roll clang {}:{}.\n\n{}".format(
       clang_old_revision, clang_svn_revision, commit_message)])
 
-  Git(["cl", "upload", "-f"])
+  Git(["cl", "upload", "-f", "--bypass-hooks"])
   Git(["cl", "try", "-b", "linux_upload_clang", "-r", git_revision])
   Git(["cl", "try", "-b", "mac_upload_clang", "-r", git_revision])
   Git(["cl", "try", "-b", "win_upload_clang", "-r", git_revision])