[release] Make auto-push process use the bot-commit label

This lands the CLs for creating V8 roll branches without TBR.

No-Try: true
Bug: chromium:1176141
Change-Id: I67defe7e0337f6beb3db2e198dc2cf87f1345ec1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3067320Reviewed-by: Liviu Rau <liviurau@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#76038}

tools/release/create_release.py

@@ -137,7 +137,7 @@ class CommitBranch(Step):
 
   def RunStep(self):
     self["commit_title"] = "Version %s" % self["version"]
-    text = "%s\n\nTBR=%s" % (self["commit_title"], self._options.reviewer)
+    text = "%s" % (self["commit_title"])
     TextToFile(text, self.Config("COMMITMSG_FILE"))
 
     self.GitCommit(file_name=self.Config("COMMITMSG_FILE"))
@@ -153,7 +153,10 @@ class LandBranch(Step):
       self.GitUpload(force=True,
                      bypass_hooks=True,
                      no_autocc=True,
+                     set_bot_commit=True,
                      message_file=self.Config("COMMITMSG_FILE"))
+    # TODO(crbug.com/1176141): This might need to go through CQ.
+    # We'd need to wait for it to land and then tag it.
     cmd = "cl land --bypass-hooks -f"
     if self._options.dry_run:
       print("Dry run. Command:\ngit %s" % cmd)

tools/release/test_scripts.py

@@ -433,9 +433,7 @@ test_tag
     # The version file on master has build level 5.
     self.WriteFakeVersionFile(build=5)
 
-    commit_msg = """Version 3.22.5
-
-TBR=reviewer@chromium.org"""
+    commit_msg = """Version 3.22.5"""
 
     def CheckVersionCommit():
       commit = FileToText(TEST_CONFIG["COMMITMSG_FILE"])
@@ -469,7 +467,7 @@ TBR=reviewer@chromium.org"""
       Cmd("git commit -aF \"%s\"" % TEST_CONFIG["COMMITMSG_FILE"], "",
           cb=CheckVersionCommit),
       Cmd("git cl upload --send-mail "
-          "-f --bypass-hooks --no-autocc --message-file "
+          "-f --set-bot-commit --bypass-hooks --no-autocc --message-file "
           "\"%s\"" % TEST_CONFIG["COMMITMSG_FILE"], ""),
       Cmd("git cl land --bypass-hooks -f", ""),
       Cmd("git fetch", ""),