LU-12572 tests: wait longer to clean up files

LU-12572 tests: wait longer to clean up files

Occasionally if a VM test node is busy after creating many files,
then it may take slightly longer to clean up at subtest completion.

Wait longer instead of failing the subtest and needing a full rerun.
This affects subtests like sanity-quota/8, sanity-pfl/20b, etc.

Test-Parameters: trivial
Test-Parameters: testlist=sanity-quota env=ONLY=8,ONLY_MINUTES=30
Test-Parameters: testlist=sanity-pfl env=ONLY=20b,ONLY_MINUTES=30
Fixes: c44b2bea1b ("LU-15179 tests: add trap cleanup_quota_test")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I0c48a0e45a2423bb79ad886e5246e6a8ff50041e
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/57704
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Patrick Farrell <pfarrell@whamcloud.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>