[OpenMP, gimplifier] 'inform' after 'error' diagnostic

[OpenMP, gimplifier] 'inform' after 'error' diagnostic

This is not a thorough review of the code, just a few cases I noticed while
scanning 'gcc/gimplify.c' for "enclosing".

	gcc/
	* gimplify.c (omp_notice_threadprivate_variable)
	(omp_default_clause, omp_notice_variable): 'inform' after 'error'
	diagnostic.  Adjust all users.
	gcc/testsuite/
	* c-c++-common/gomp/default-1.c: Update.
	* c-c++-common/gomp/defaultmap-3.c: Likewise.
	* c-c++-common/gomp/order-4.c: Likewise.
	* g++.dg/gomp/parallel-2.C: Likewise.
	* g++.dg/gomp/predetermined-1.C: Likewise.
	* g++.dg/gomp/sharing-1.C: Likewise.
	* gcc.dg/gomp/appendix-a/a.24.1.c: Likewise.
	* gcc.dg/gomp/parallel-2.c: Likewise.
	* gcc.dg/gomp/pr44085.c: Likewise.
	* gcc.dg/gomp/sharing-1.c: Likewise.
	* gcc.dg/gomp/vla-1.c: Likewise.
	* gfortran.dg/gomp/appendix-a/a.24.1.f90: Likewise.
	* gfortran.dg/gomp/crayptr3.f90: Likewise.
	* gfortran.dg/gomp/pr33439.f90: Likewise.
	* gfortran.dg/gomp/pr44036-1.f90: Likewise.
	* gfortran.dg/gomp/pr44085.f90: Likewise.
	* gfortran.dg/gomp/pr44536.f90: Likewise.
	* gfortran.dg/gomp/pr94672.f90: Likewise.
	* gfortran.dg/gomp/sharing-1.f90: Likewise.
	* gfortran.dg/gomp/sharing-2.f90: Likewise.
	* gfortran.dg/gomp/sharing-3.f90: Likewise.