memblock tests: Add memblock_alloc_from tests for bottom up

Add checks for memblock_alloc_from for bottom up allocation direction.
The tested scenarios are:
  - Not enough space to allocate memory at the minimal address
  - Minimal address parameter is smaller than the start address
    of the available memory
  - Minimal address parameter is too close to the end of the available
    memory

Add test case wrappers to test both directions in the same context.

Signed-off-by: Karolina Drobnik <karolinadrobnik@gmail.com>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/506cf5293c8a21c012b7ea87b14af07754d3e656.1646055639.git.karolinadrobnik@gmail.com