bootperf: reset tmp_dir for each iteration

This fixes an error when bootperf runs with multiple iterations without
the -k option (which saves system log files) and recreates the tmp dir
for each iteration.

BUG=b:166744231
TEST=bootperf $IP_ADDR 10

Change-Id: I1c10ac562fa3a00c3a2987b3058d38b445f18f0f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/2738903
Reviewed-by: Kuang-che Wu <kcwu@chromium.org>
Reviewed-by: Chinglin Yu <chinglinyu@chromium.org>
Tested-by: Chinglin Yu <chinglinyu@chromium.org>
Commit-Queue: Chinglin Yu <chinglinyu@chromium.org>
1 file changed