bug#44241: time-tests-display-time-update fails on hosts with mail

[Glenn Morris]

Package: emacs
Version: 28.0.50
Severity: minor

time-tests-display-time-update fails on a host with mail:

Test time-tests-display-time-update condition:
    (ert-test-failed
     ((should
       (string-match
        (rx string-start ... digit ":" digit digit ... " " ... ...)
        display-time-string))
      :form
      (string-match 
"\\`[[:digit:]]?[[:digit:]]:[[:digit:]][[:digit:]]\\(?:[AP]M\\)? 
\\(?:[[:digit:]]\\|\\.\\)+\\'"
                    #("7:48AM 1.02 Mail" 0 6
                      (help-echo "Mon Oct 26, 2020")
                      6 11
                      (local-map ... mouse-face mode-line-highlight help-echo 
"System load average for past 5 minutes; mouse-2: next")
                      12 16
                      (local-map ... mouse-face mode-line-highlight help-echo 
"You have new mail; mouse-2: Read mail" face nil display ...)))
      :value nil))
   FAILED  3/8  time-tests-display-time-update (0.000708 sec)