Use separate db dir for different tests hoping to remove flakiness (#8147)

Summary:
DBWALTestWithParam relies on `SstFileManager` to have the expected behavior. However, if this test shares
db directories with other DBSSTTest, then the SstFileManager may see non-empty data, thus will change its
behavior to be different from expectation, introducing flakiness.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8147

Test Plan: make check

Reviewed By: jay-zhuang

Differential Revision: D27553362

Pulled By: riversand963

fbshipit-source-id: a2d86343e8e2220bc553b6695ce87dd21a97ddec

db/db_sst_test.cc

@@ -751,10 +751,11 @@ TEST_F(DBSSTTest, RateLimitedWALDelete) {
 }
 
 class DBWALTestWithParam
-    : public DBSSTTest,
+    : public DBTestBase,
       public testing::WithParamInterface<std::tuple<std::string, bool>> {
  public:
-  DBWALTestWithParam() {
+  explicit DBWALTestWithParam()
+      : DBTestBase("/db_wal_test_with_params", /*env_do_fsync=*/true) {
     wal_dir_ = std::get<0>(GetParam());
     wal_dir_same_as_dbname_ = std::get<1>(GetParam());
   }