Fix undeterministic failure of DBTest.GetPropertiesOfAllTablesTest

Summary: DBTest.GetPropertiesOfAllTablesTest generates four files and expects four files there, but a L0->L1 comapction can trigger to compact to one single file. Fix it by raising level 0 number of file compaction trigger

Test Plan: Run it many times and see it never fails.

Reviewers: kradhakrishnan, IslamAbdelRahman, yhchiang, anthony

Reviewed By: anthony

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D42789

db/db_test.cc

@@ -420,7 +420,7 @@ TEST_F(DBTest, ParanoidFileChecks) {
 
 TEST_F(DBTest, GetPropertiesOfAllTablesTest) {
   Options options = CurrentOptions();
-  options.max_background_flushes = 0;
+  options.level0_file_num_compaction_trigger = 8;
   Reopen(options);
   // Create 4 tables
   for (int table = 0; table < 4; ++table) {