memblock tests: set memblock_debug to enable memblock_dbg() messages

If Memblock simulator was compiled with MEMBLOCK_DEBUG=1, set
memblock_debug to 1 so that memblock_dbg() will print debug information
when memblock functions are tested in Memblock simulator.

Signed-off-by: Rebecca Mckeever <remckee0@gmail.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/aee4200cce1c09992ed055006a81fde1b6b5b567.1656907314.git.remckee0@gmail.com