openmp: Fix up finish_omp_target_clauses [PR108286]

openmp: Fix up finish_omp_target_clauses [PR108286]

The comment in the loop says that we shouldn't add a map clause if such
a clause exists already, but the loop was actually using OMP_CLAUSE_DECL
on any clause.  Target construct can have various clauses which don't
have OMP_CLAUSE_DECL at all (e.g. nowait, device or if) or clause
where it means something different (e.g. privatization clauses, allocate,
depend).

So, only check OMP_CLAUSE_DECL on OMP_CLAUSE_MAP clauses.

2023-01-05  Jakub Jelinek  <jakub@redhat.com>

	PR c++/108286
	* semantics.cc (finish_omp_target_clauses): Ignore clauses other than
	OMP_CLAUSE_MAP.

	* testsuite/libgomp.c++/pr108286.C: New test.