Disable ReadYourOwnWriteStress when run under Valgrind (#5671)

Summary:
It sometimes times out when run under valgrind taking around 20m. The patch skips the test under Valgrind.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5671

Differential Revision: D16652382

Pulled By: maysamyabandeh

fbshipit-source-id: 0f6f4f76d37337d56226b689e01b14523dd07aae

utilities/transactions/write_unprepared_transaction_test.cc

@@ -115,6 +115,7 @@ TEST_P(WriteUnpreparedTransactionTest, ReadYourOwnWrite) {
   }
 }
 
+#ifndef ROCKSDB_VALGRIND_RUN
 TEST_P(WriteUnpreparedTransactionTest, ReadYourOwnWriteStress) {
   // This is a stress test where different threads are writing random keys, and
   // then before committing or aborting the transaction, it validates to see
@@ -294,6 +295,7 @@ TEST_P(WriteUnpreparedTransactionTest, ReadYourOwnWriteStress) {
     }
   }
 }
+#endif  // ROCKSDB_VALGRIND_RUN
 
 // This tests how write unprepared behaves during recovery when the DB crashes
 // after a transaction has either been unprepared or prepared, and tests if