Pin desugared library archive bot at a fixed revision

This is a initial workaround to be able to control the revision
used for building the release on the bots.

Bug: b/244156342
Change-Id: Ie26fdafe32880a11fb9d95ca037543fba18df9ee
diff --git a/tools/git_utils.py b/tools/git_utils.py
index 1ce0a0a..542947a 100644
--- a/tools/git_utils.py
+++ b/tools/git_utils.py
@@ -11,6 +11,12 @@
   utils.PrintCmd(cmd)
   return subprocess.check_call(cmd)
 
+def GitCheckout(revision, checkout_dir):
+  with utils.ChangedWorkingDirectory(checkout_dir):
+    cmd = ['git', 'checkout', revision]
+    utils.PrintCmd(cmd)
+    return subprocess.check_call(cmd)
+
 def GetHeadRevision(checkout_dir, use_main=False):
   revision_from = 'origin/main' if use_main else 'HEAD'
   cmd = ['git', 'rev-parse', revision_from]