test: move test that creates 1Gb file to pummel

Fixes: #16601

PR-URL: #27053
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Signed-off-by: Beth Griggs <Bethany.Griggs@uk.ibm.com>

Author: Trott