message: Have sanity build output a Bazel test summary XML file.
  This should avoid needing to download the full log file to find out which check failed, hopefully preventing inadvertent force submits.
diff: @@ -702,23 +702,37 @@ done
  # Print summary of build results
  COUNTER=0
  echo "==== Summary of sanity check results ===="
  +TESTCASE_XML=''
  while [[ ${COUNTER} -lt "${#SANITY_STEPS[@]}" ]]; do
  INDEX=COUNTER
  ((INDEX++))
  echo "${INDEX}. ${SANITY_STEPS[COUNTER]}: ${SANITY_STEPS_DESC[COUNTER]}"
  + TESTCASE_XML="${TESTCASE_XML} <testcase name=\"${SANITY_STEPS_DESC[COUNTER]}\" status=\"run\" classname=\"\" time=\"0\">"
  +
  if [[ ${STEP_EXIT_CODES[COUNTER]} == "0" ]]; then
  printf " ${COLOR_GREEN}PASS${COLOR_NC}\n"
  else
  printf " ${COLOR_RED}FAIL${COLOR_NC}\n"
  + TESTCASE_XML="${TESTCASE_XML} <failure message=\"\" type=\"\"/>"
  fi
  + TESTCASE_XML="${TESTCASE_XML} </testcase>"
  +
  ((COUNTER++))
  done
  echo
  echo "${FAIL_COUNTER} failed; ${PASS_COUNTER} passed."
  +mkdir -p "${KOKORO_ARTIFACTS_DIR}/${KOKORO_JOB_NAME}/summary"
  +echo '<?xml version="1.0" encoding="UTF-8"?>'\
  + '<testsuites name="1" tests="1" failures="0" errors="0" time="0">'\
  + '<testsuite name="Kokoro Summary" tests="'"$((FAIL_COUNTER + PASS_COUNTER))"\
  + '" failures="'"${FAIL_COUNTER}"'" errors="0" time="0">'\
  + "${TESTCASE_XML}"'</testsuite></testsuites>'\
  + > "${KOKORO_ARTIFACTS_DIR}/${KOKORO_JOB_NAME}/summary/sponge_log.xml"
  +
  echo
  if [[ ${FAIL_COUNTER} == "0" ]]; then
  printf "Sanity checks ${COLOR_GREEN}PASSED${COLOR_NC}\n"
  