gclient: Fetch refs/{branch-heads,tags}/* if needed.

If we're asked to sync a repo to branch-heads or tags,
make sure we fetch refs/branch-heads/* and refs/tags/* even if
--with-branch-heads or --with-tags was not passed.

Bug: 938160
Change-Id: I04de8e7762c83322692d9551d057ec803fd2ac9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1506420Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

gclient_scm.py

@@ -507,6 +507,11 @@ class GitWrapper(SCMWrapper):
       verbose = ['--verbose']
       printed_path = True
 
+    if revision.startswith('refs/branch-heads'):
+      options.with_branch_heads = True
+    if revision.startswith('refs/tags'):
+      options.with_tags = True
+
     remote_ref = scm.GIT.RefToRemoteRef(revision, self.remote)
     if remote_ref:
       # Rewrite remote refs to their local equivalents.