memblock tests: add test for memblock_set_node

Add a test to check memblock_set_node() behavior.

And create a corner case in which the memblock.reserved array is doubled
during memblock_set_node(). And finally make sure all regions in
memblock.reserved are with valid node id.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
CC: Mike Rapoport <rppt@kernel.org>
CC: Yajun Deng <yajun.deng@linux.dev>
Link: https://lore.kernel.org/r/20250318071948.23854-4-richard.weiyang@gmail.com


Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>