Before this patch vma sizes were hardcoded and weren't derived
from PAGE_SIZE value.
But all the actions with these vmas are based on PAGE_SIZE value.
That's why maps008 on PowerPC with "huge" PAGE_SIZE of 64k was simply
terminating due to invalid memory access.

This commit sets vma sizes to safe values derived from PAGE_SIZE.
New sizes are enough to perform all the actions test does with vmas.
Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Eugene Batalov <eabatalov89@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>