Fortran/openmp: Add support for 2 argument num_teams clause

Fortran/openmp: Add support for 2 argument num_teams clause

Fortran part to commit r12-5146-g48d7327f2aaf65

gcc/fortran/ChangeLog:

	* gfortran.h (struct gfc_omp_clauses): Rename num_teams to
	num_teams_upper, add num_teams_upper.
	* dump-parse-tree.c (show_omp_clauses): Update to handle
	lower-bound num_teams clause.
	* frontend-passes.c (gfc_code_walker): Likewise
	* openmp.c (gfc_free_omp_clauses, gfc_match_omp_clauses,
	resolve_omp_clauses): Likewise.
	* trans-openmp.c (gfc_trans_omp_clauses, gfc_split_omp_clauses,
	gfc_trans_omp_target): Likewise.

libgomp/ChangeLog:

	* testsuite/libgomp.fortran/teams-1.f90: New test.