LU-18075 tests: fiemap test for sparse files

LU-18075 tests: fiemap test for sparse files

New "Check fiemap for sparse files" test shows the
memory corruption without the following fix:
  LU-17110 llite: fix slab corruption with fm_extent_count=0

Test-Parameters: trivial testlist=sanity env=ONLY=44f,ONLY_REPEAT=10,NUMFILES_44f=20
Signed-off-by: Elena Gryaznova <elena.gryaznova@hpe.com>
Signed-off-by: Vladimir Saveliev <vladimir.saveliev@hpe.com>
HPE-bug-id: LUS-11952,LUS-12040
Reviewed-by: Andrew Perepechko <andrew.perepechko@hpe.com>
Reviewed-by: Vladimir Saveliev <vladimir.saveliev@hpe.com>
Change-Id: I22034c7937366d9ea4b2b3f02fd7085d7ebe7e10
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55883
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>