LU-16167 obdclass: fix lctl llog_print with skipped records

LU-16167 obdclass: fix lctl llog_print with skipped records

The 2a5b50d ignores the skipped records in configuration llog.
But if ioctl OBD_IOC_LLOG_PRINT return 0 record to display,
jt_llog_print_iter() will stop the processing and ignore the
non-skipped records at the end of the llog.

This patch returns to user space if the last index processed
(by llog_print_cb) is the last of llog file. If true,
jt_llog_print_iter() stops the processing.

Add regression test "conf-sanity test_123ai" for this issue.

Lustre-change: https://review.whamcloud.com/48586
Lustre-commit: c6da54aa7546440339265c644538d3d109e46bde

Fixes: 2a5b50d ("LU-15142 lctl: fixes for set_param -P and llog_print")
Test-Parameters: testlist=conf-sanity env=ONLY=123ai,SLOW=yes,ONLY_REPEAT=10
Signed-off-by: Etienne AUJAMES <etienne.aujames@cea.fr>
Change-Id: I78395268c57555e4fd2a4048ccf5b6132ca2877f
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alexander <alexander.boyko@hpe.com>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/51221
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alexander Boyko <alexander.boyko@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>