[OpenACC privatization] Analyze 'lookup_decl'-translated DECL [PR90115, PR102330...

[OpenACC privatization] Analyze 'lookup_decl'-translated DECL [PR90115, PR102330, PR104774]

... so that it matches what we analyze and what we action on.
Fix-up for commit 29a2f51806c5b30e17a8d0e9ba7915a3c53c34ff "openacc:
Add support for gang local storage allocation in shared memory [PR90115]".

	PR middle-end/90115
	PR middle-end/102330
	PR middle-end/104774
	gcc/
	* omp-low.cc (oacc_privatization_candidate_p)
	(oacc_privatization_scan_clause_chain)
	(oacc_privatization_scan_decl_chain, lower_oacc_private_marker):
	Analyze 'lookup_decl'-translated DECL.
	gcc/testsuite/
	* c-c++-common/goacc/kernels-decompose-pr104061-1-3.c: Adjust.
	* c-c++-common/goacc/kernels-decompose-pr104061-1-4.c: Likewise.
	* c-c++-common/goacc/kernels-decompose-pr104132-1.c: Likewise.
	* c-c++-common/goacc/kernels-decompose-pr104133-1.c: Likewise.
	* c-c++-common/goacc/kernels-decompose-pr104774-1.c: Likewise.
	* c-c++-common/goacc/privatization-1-compute-loop.c: Likewise.
	* c-c++-common/goacc/privatization-1-compute.c: Likewise.
	* c-c++-common/goacc/privatization-1-routine_gang-loop.c:
	Likewise.
	* c-c++-common/goacc/privatization-1-routine_gang.c: Likewise.
	* gfortran.dg/goacc-gomp/pr102330-1.f90: Likewise, and subsume...
	* gfortran.dg/goacc-gomp/pr102330-2.f90: ... this file, and...
	* gfortran.dg/goacc-gomp/pr102330-3.f90: ... this file.
	* gfortran.dg/goacc/privatization-1-compute-loop.f90: Adjust.
	* gfortran.dg/goacc/privatization-1-compute.f90: Likewise.
	* gfortran.dg/goacc/privatization-1-routine_gang-loop.f90:
	Likewise.
	* gfortran.dg/goacc/privatization-1-routine_gang.f90: Likewise.
	libgomp/
	* testsuite/libgomp.oacc-c-c++-common/kernels-decompose-1.c:
	Enhance.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-local-worker-1.c:
	Adjust.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-local-worker-2.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-local-worker-3.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-local-worker-4.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-local-worker-5.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-loop-vector-1.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-loop-vector-2.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-loop-worker-2.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-loop-worker-3.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-loop-worker-4.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-loop-worker-5.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-loop-worker-6.c:
	Likewise.
	* testsuite/libgomp.oacc-c-c++-common/kernels-private-vars-loop-worker-7.c:
	Likewise.
	* testsuite/libgomp.oacc-fortran/optional-private.f90: Likewise.
	* testsuite/libgomp.oacc-fortran/privatized-ref-1.f95: Likewise.
	* testsuite/libgomp.oacc-fortran/privatized-ref-2.f90: Likewise.