util: promote u_debug_memory.c to src/util

util: promote u_debug_memory.c to src/util

When os_memory_debug.h was promoted to src/util, this source-file on
which it depends on when the debug-flag is set on windows was left
out. So let's move this also.

It doesn't seem there's any way of triggering this issue right now, but
it seems better to correct this to avoid this from biting us in the ass
in the future.

Fixes: 88c4680b5a5 ("util: promote u_memory to src/util")
Reviewed-by: Dylan Baker <dylan@pnwbakers>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3844>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3844>