MDEV-5081 - Simple performance improvement for MariaDB

Currently fast mutexes have lower throuput compared to normal mutexes.
Remove them from release build configuration.

cmake/build_configurations/mysql_release.cmake

@@ -154,9 +154,6 @@ IF(UNIX)
       # libmysqld.so will depend on libaio.so
       SET(LIBMYSQLD_SO_EXTRA_LIBS aio)
     ENDIF()
-
-    # Enable fast mutexes on Linux
-    OPTION(WITH_FAST_MUTEXES "" ON)
   ENDIF()
 
 ENDIF()