Reduce runtime of compact_on_deletion_collector_test (#4779)

Summary:
It sometimes times out with it is run with TSAN. The patch reduces the iteration from 50 to 30. This reduces the normal runtime from 5.2 to 3.1 seconds and should similarly address the TSAN timeout problem.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4779

Differential Revision: D13456862

Pulled By: maysamyabandeh

fbshipit-source-id: fdc0ad7d781b1c33b771d2415ff5fa2f1b5e2537

utilities/table_properties_collectors/compact_on_deletion_collector_test.cc

@@ -40,7 +40,7 @@ int main(int /*argc*/, char** /*argv*/) {
   // randomize tests
   rocksdb::Random rnd(301);
   const int kMaxTestSize = 100000l;
-  for (int random_test = 0; random_test < 50; random_test++) {
+  for (int random_test = 0; random_test < 30; random_test++) {
     int window_size = rnd.Uniform(kMaxTestSize) + 1;
     int deletion_trigger = rnd.Uniform(window_size);
     window_sizes.emplace_back(window_size);