LU-16677 utils: add bitfields and ifdefs to wiretest

LU-16677 utils: add bitfields and ifdefs to wiretest

Add CHECK_BITFIELD() for "checking" bitfields in data structures
(currently only adds a comment to wiretest.c, maybe improve later).

Add CHECK_COND_START/FINISH() for adding #ifdef/#endif conditions
into wiretest, mainly for structs not used by (upstream) client.

Test-Parameters: trivial
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I8ecc4bdd5b5d651faa42f65ce8ea46da003ebbe5
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/50479
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Alexander Zarochentsev <alexander.zarochentsev@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>