tests: add reshape size consistency tests script lvconvert-raid-reshape-size.sh

tests: add reshape size consistency tests script lvconvert-raid-reshape-size.sh

Calculates expected size before/after reshapes adding/removing stripes
to/from RaidLVs with levels 4/5/6/10 and compares it with the actual
one the block layer shows.  Stripes reshaped to are listed in the
tst_stripes variable.  mkfs/fsck/resize2fs the respective RaidLVs
to confirm ext4 can be resized accordingly without issues.