Enable crash test to run BlobDB together with user-defined timestamp (#11199)

Summary:
I missed a stress test code sanity check when enabling this combination of tests. This PR addresses that, the "iter_start_ts" function for user defined timestamp feature is not supported when BlobDB is enabled. It's disabled for now.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11199

Test Plan:
Locally always enable BlobDB and run
tools/db_crashtest.py --stress_cmd=./db_stress --cleanup_cmd='' --enable_ts whitebox --random_kill_odd 888887

Reviewed By: ltamasi

Differential Revision: D43245657

Pulled By: jowlyzhang

fbshipit-source-id: 4cae19817bb1afd50a76f9e0e49f006fb5c0b211

db_stress_tool/db_stress_test_base.cc

@@ -2901,7 +2901,9 @@ void StressTest::MaybeUseOlderTimestampForRangeScan(ThreadState* thread,
   read_opts.timestamp = &ts_slice;
 
   // TODO (yanqin): support Merge with iter_start_ts
-  if (!thread->rand.OneInOpt(3) || FLAGS_use_merge || FLAGS_use_full_merge_v1) {
+  // TODO (yuzhangyu): support BlobDB with iter_start_ts
+  if (!thread->rand.OneInOpt(3) || FLAGS_use_merge || FLAGS_use_full_merge_v1 ||
+      FLAGS_enable_blob_files) {
     return;
   }
 
@@ -2926,10 +2928,6 @@ void CheckAndSetOptionsForUserTimestamp(Options& options) {
     fprintf(stderr, "TransactionDB does not support timestamp yet.\n");
     exit(1);
   }
-  if (FLAGS_enable_blob_files || FLAGS_use_blob_db) {
-    fprintf(stderr, "BlobDB not supported with timestamp.\n");
-    exit(1);
-  }
   if (FLAGS_test_cf_consistency || FLAGS_test_batches_snapshots) {
     fprintf(stderr,
             "Due to per-key ts-seq ordering constraint, only the (default) "