Temporarily Disable DBTest2.PresetCompressionDict (#5003)

Summary:
DBTest2.PresetCompressionDict is flaky. Temparily disable it for now.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5003

Differential Revision: D14139505

Pulled By: siying

fbshipit-source-id: ebf1872d364b76b2cb021b489ea2f17ee997116a

db/db_test2.cc

@@ -1036,7 +1036,8 @@ TEST_F(DBTest2, WalFilterTestWithColumnFamilies) {
   ASSERT_TRUE(index == keys_cf.size());
 }
 
-TEST_F(DBTest2, PresetCompressionDict) {
+// Temporarily disable it because the test is flaky.
+TEST_F(DBTest2, DISABLED_PresetCompressionDict) {
   // Verifies that compression ratio improves when dictionary is enabled, and
   // improves even further when the dictionary is trained by ZSTD.
   const size_t kBlockSizeBytes = 4 << 10;