Assumed-size arrays with non-lexical data mappings

Assumed-size arrays with non-lexical data mappings

	gcc/
	* gimplify.c (gimplify_adjust_omp_clauses_1): Raise error for
	assumed-size arrays in map clauses for Fortran/OpenMP.
	* omp-low.c (lower_omp_target): Set the size of assumed-size Fortran
	arrays to one to allow use of data already mapped on the offload device.

	gcc/fortran/
	* trans-openmp.c (gfc_omp_finish_clause): Change clauses mapping
	assumed-size arrays to use the GOMP_MAP_FORCE_PRESENT map type.

(cherry picked from openacc-gcc-9-branch commit
cfc73bde082700240f0ac9560c2af884cc9930d1)