[OpenACC privatization] Reject 'static', 'external' in blocks [PR90115]

[OpenACC privatization] Reject 'static', 'external' in blocks [PR90115]

	gcc/
	PR middle-end/90115
	* omp-low.c (oacc_privatization_candidate_p): Reject 'static',
	'external' in blocks.
	gcc/testsuite/
	PR middle-end/90115
	* c-c++-common/goacc/privatization-1-compute-loop.c: Update.
	* 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.
	libgomp/
	PR middle-end/90115
	* testsuite/libgomp.oacc-c-c++-common/static-variable-1.c: Update.
	* testsuite/libgomp.oacc-fortran/privatized-ref-2.f90: Likewise.