Remove wait-for-merge from gerrit client tool

Following comment in crrev.com/c/3039331, submit call
is fully synchronous.

BUG=1207955
TEST=e2e

Change-Id: I9146d43b4d4530ad5064709e418d34e3229e19ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/3049672
Commit-Queue: Xinan Lin <linxinan@chromium.org>
Reviewed-by: Anthony Polito <apolito@google.com>
Reviewed-by: Andrii Shyshkalov <tandrii@google.com>
diff --git a/git_cl.py b/git_cl.py
index 5340962..5edf440 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -1963,10 +1963,9 @@
     gerrit_util.AbandonChange(
         self.GetGerritHost(), self._GerritChangeIdentifier(), msg='')
 
-  def SubmitIssue(self, wait_for_merge=True):
+  def SubmitIssue(self):
     gerrit_util.SubmitChange(
-        self.GetGerritHost(), self._GerritChangeIdentifier(),
-        wait_for_merge=wait_for_merge)
+        self.GetGerritHost(), self._GerritChangeIdentifier())
 
   def _GetChangeDetail(self, options=None):
     """Returns details of associated Gerrit change and caching results."""
@@ -2061,7 +2060,7 @@
           resultdb=resultdb,
           realm=realm)
 
-    self.SubmitIssue(wait_for_merge=True)
+    self.SubmitIssue()
     print('Issue %s has been submitted.' % self.GetIssueURL())
     links = self._GetChangeCommit().get('web_links', [])
     for link in links: