run_test: plug tmpfile leak for skipped files
run_test: plug tmpfile leak for skipped files

BUG=none
TEST=run_tests and see no leftover files in /tmp/

Change-Id: Ieca1077c2d014afa51695aaa7af14670fbc7a0a9
Reviewed-on: https://gerrit.chromium.org/gerrit/36174
Tested-by: Zdenek Behan <483cf2a9a4e071d4fd973db6a5a78c40f490667c@chromium.org>
Reviewed-by: Mike Frysinger <8f3f75c74bd5184edcfa6534cab3c13a00a2f794@chromium.org>
Commit-Ready: Zdenek Behan <483cf2a9a4e071d4fd973db6a5a78c40f490667c@chromium.org>

coreos/chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite,bpsinc-native/src_third_party_chromite,zhang0137/chromite,coreos/chromite,zhang0137/chromite,chadversary/chromiumos.chromite,chadversary/chromiumos.chromite,zhang0137/chromite,coreos/chromite