Merge pull request #13210 from y-zeng/end2end_fix

Set GRPC_CLIENT_CHANNEL_BACKUP_POLL_INTERVAL_MS for async_end2end_test

test/cpp/end2end/async_end2end_test.cc

@@ -461,7 +461,6 @@ TEST_P(AsyncEnd2endTest, ReconnectChannel) {
   if (GetParam().inproc) {
     return;
   }
-  gpr_setenv("GRPC_CLIENT_CHANNEL_BACKUP_POLL_INTERVAL_MS", "200");
   int poller_slowdown_factor = 1;
   // It needs 2 pollset_works to reconnect the channel with polling engine
   // "poll"
@@ -2013,6 +2012,9 @@ INSTANTIATE_TEST_CASE_P(AsyncEnd2endServerTryCancel,
 }  // namespace grpc
 
 int main(int argc, char** argv) {
+  // Change the backup poll interval from 5s to 200ms to speed up the
+  // ReconnectChannel test
+  gpr_setenv("GRPC_CLIENT_CHANNEL_BACKUP_POLL_INTERVAL_MS", "200");
   grpc_test_init(argc, argv);
   gpr_tls_init(&g_is_async_end2end_test);
   ::testing::InitGoogleTest(&argc, argv);