openmp: Avoid calling operand_equal_p on OMP_CLAUSEs [PR103704]

openmp: Avoid calling operand_equal_p on OMP_CLAUSEs [PR103704]

On OMP_CLAUSEs we reuse TREE_TYPE as CP_OMP_CLAUSE_INFO in the C++ FE.
This confuses the hashing code that operand_equal_p does when checking.
There is really no reason to compare OMP_CLAUSEs against expressions
like captured this, they will never compare equal.

2021-12-15  Jakub Jelinek  <jakub@redhat.com>

	PR c++/103704
	* semantics.c (finish_omp_target_clauses_r): For OMP_CLAUSEs
	just walk subtrees.

	* g++.dg/gomp/pr103704.C: New test.