vmem: implementation of vmem_check

Validate pool consistency.
-Check wrong data in header
-Check not zeroed values inside a zeroed pages
-Check data structures are outside of memory region
-Check conflict memory regions between pools
Merge pull request #34 from spawlows/vmem-pool-check-merged

vmem: implementation of vmem_check
common: fix few tests to work under bullseye

Fix execute tests under coverage tool bullseye:
-vmem_valgrind
-blk_nblock
-blk_rw