In xref-location-marker, handle deleted file or outdated xref location nicely

* lisp/progmodes/xref.el (xref-location-marker): Add ignore-errors.
1 job for master in 90 minutes and 1 second (queued for 5 seconds)
Status Job ID Name Coverage
  Test
failed #3905
test-all

01:30:01

 
Name Stage Failure
failed
test-all Test The script exceeded the maximum execution time set for the job
  ELC      lisp/textmodes/dns-mode-tests.elc
GEN lisp/textmodes/dns-mode-tests.log
ELC lisp/textmodes/fill-tests.elc
GEN lisp/textmodes/fill-tests.log
ELC lisp/textmodes/mhtml-mode-tests.elc
GEN lisp/textmodes/mhtml-mode-tests.log
ELC lisp/textmodes/page-tests.elc
Pulling docker image gitlab/gitlab-runner-helper:x86_64-d0b76032 ...
ERROR: Job failed: execution took longer than 1h30m0s seconds