[#7889] [tests] Fix PgIndexBackfillTest.Large

Summary: Fix assert to account for lowered rpc timeout (in 2fcae00)  which may result in more than one backfill RPC per tablet.

Test Plan: ybd asan --cxx-test pg_index_backfill-test --gtest_filter PgIndexBackfillTest.Large  -n 100 --tp 1

Reviewers: jason

Reviewed By: jason

Subscribers: ybase

Differential Revision: https://phabricator.dev.yugabyte.com/D12951

src/yb/yql/pgwrapper/pg_index_backfill-test.cc

@@ -376,7 +376,7 @@ TEST_F(PgIndexBackfillTest, YB_DISABLE_TEST_IN_TSAN(Large)) {
   TestLargeBackfill(kNumRows);
   int expected_calls = cluster_->num_tablet_servers() * kTabletsPerServer;
   auto actual_calls = ASSERT_RESULT(TotalBackfillRpcCalls(cluster_.get()));
-  ASSERT_EQ(actual_calls, expected_calls);
+  ASSERT_GE(actual_calls, expected_calls);
 }
 
 class PgIndexBackfillTestChunking : public PgIndexBackfillTest {