ASAN: RockDB doesn't free ThreadLocalPtr::StaticMeta instance

ThreadLocalPtr::StaticMeta instance is a singleton.
It is created once, immediately when ha_rocksdb.so is dlopened [1] and it doesn't seem to be freed anywhere. This triggers leak sanitizer in ASAN builds. It can perhaps exhaust memory if one installs/uninstalls (or runs show plugin soname) in a loop.

[1] static variable rocksdb_db_options initialized by calling rdb_init_rocksdb_db_options() that calls DBOptions::DBOptions(), Env::Default(), ThreadLocalPtr::InitSingletons(), ThreadLocalPtr::Instance().

Explicit delete seems to help:

diff --git a/util/thread_local.cc b/util/thread_local.cc

--- a/util/thread_local.cc

+++ b/util/thread_local.cc

@@ -335,6 +335,7 @@ ThreadLocalPtr::StaticMeta::StaticMeta()

       if (tls_) {

         OnThreadExit(tls_);

       }

+      delete Instance();

     }

   } a;

 #endif  // !defined(OS_WIN)