openmp: For default(none) ignore variables created by ubsan_create_data [PR64888]

openmp: For default(none) ignore variables created by ubsan_create_data [PR64888]

We weren't ignoring the ubsan variables created by c-ubsan.c before gimplification
(others are added later).  One way to fix this would be to introduce further
UBSAN_ internal functions and lower it later (sanopt pass) like other ifns,
this patch instead recognizes those magic vars by name/name of type and DECL_ARTIFICIAL
and TYPE_ARTIFICIAL.

2021-10-21  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/64888
gcc/c-family/
	* c-omp.c (c_omp_predefined_variable): Return true also for
	ubsan_create_data created artificial variables.
gcc/testsuite/
	* c-c++-common/ubsan/pr64888.c: New test.