LU-16953 tests: wait longer in replay-dual/test_31

LU-16953 tests: wait longer in replay-dual/test_31

Wait until file was created in replay-dual/test_31.

Lustre-change: https://review.whamcloud.com/51621
Lustre-commit: TBD (from eed10c2ef36c7e1aebec27ce943b80bd0174ddf0)

Signed-off-by: Lei Feng <flei@whamcloud.com>
Test-Parameters: trivial testlist=replay-dual env=ONLY=31,ONLY_REPEAT=100
Change-Id: I847beb51d53e667f1599c9693aa5eb099dcf9435
Reviewed-on: https://review.whamcloud.com/c/ex/lustre-release/+/51622
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Alex Deiter <alex.deiter@gmail.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>