mapi: Remove usage of _glapi_check_multithread and _glapi_destroy_multithread

They are empty stub functions now so have no need call to them

Signed-off-by: Yonggang Luo <luoyonggang@gmail.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Acked-by: Jose Fonseca <jfonseca@vmware.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17814>

src/mesa/main/context.c

@@ -1493,11 +1493,6 @@ _mesa_make_current( struct gl_context *newCtx,
       st_glFlush(curCtx, 0);
    }
 
-   /* Call this periodically to detect when the user has begun using
-    * GL rendering from multiple threads.
-    */
-   _glapi_check_multithread();
-
    if (!newCtx) {
       _glapi_set_dispatch(NULL);  /* none current */
       /* We need old ctx to correctly release Draw/ReadBuffer