Merge pull request #14192 from sreecha/e2e_test

Set GRPC_CLIENT_CHANNEL_BACKUP_POLL_INTERVAL_MS at the beginning of the test.

test/cpp/end2end/end2end_test.cc

@@ -706,7 +706,6 @@ TEST_P(End2endTest, 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"
@@ -1828,6 +1827,7 @@ INSTANTIATE_TEST_CASE_P(ResourceQuotaEnd2end, ResourceQuotaEnd2endTest,
 }  // namespace grpc
 
 int main(int argc, char** argv) {
+  gpr_setenv("GRPC_CLIENT_CHANNEL_BACKUP_POLL_INTERVAL_MS", "200");
   grpc_test_init(argc, argv);
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();