diagnostics: Fix selftest ICE in certain locales [PR107722]

As reported in the PR, since special_fname_builtin () call has been
introduced, the diagnostics code compares filename against _("<built-in>")
rather than "<built-in>", which means that if self tests are performed
with the string being translated, one self-test fails.
The following patch fixes that.

2022-11-23  Jakub Jelinek  <jakub@redhat.com>

	PR bootstrap/107722
	* diagnostic.cc (test_diagnostic_get_location_text): Test
	special_fname_builtin () rather than "<built-in>" and expect
	special_fname_builtin () concatenated with ":" for it.
1 file changed