[sanitizer] Remove set -exu from the script

It's already in "*_functions.sh"

Author: vitalybuka

zorg/buildbot/builders/sanitizers/buildbot_bootstrap_hwasan.sh

@@ -1,9 +1,5 @@
 #!/usr/bin/env bash
 
-set -x
-set -e
-set -u
-
 HERE="$(cd $(dirname $0) && pwd)"
 . ${HERE}/buildbot_functions.sh