Make generation of JUnit test reports more robust.

Make generation of JUnit test reports more robust.

* lisp/emacs-lisp/ert.el (ert-load-file-name): New defvar.
(ert-write-junit-test-report): Use it.  Make detection of selector
more robust.  Protect calls of `xml-escape-string' with 'noerror.

* test/infra/Makefile.in (subdir_template): Use "make -k ...".

* test/infra/gitlab-ci.yml (test-filenotify-gio):
Adapt make_params in order to get a JUnit test report.
(test-native-comp-speed0): Use "make -k ...".

* test/infra/test-jobs.yml: Regenerate.

* test/lisp/progmodes/perl-mode-tests.el (top):
Set `ert-load-file-name'.