libgomp: Fix 'target enter data' with always pointer

As GOMP_MAP_ALWAYS_POINTER operates on the previous map item, ensure that
with 'target enter data' both are passed together to gomp_map_vars_internal.

libgomp/ChangeLog:

	* target.c (gomp_map_vars_internal): Add 'i > 0' before doing a
	kind check.
	(GOMP_target_enter_exit_data): If the next map item is
	GOMP_MAP_ALWAYS_POINTER map it together with the current item.
	* testsuite/libgomp.fortran/target-enter-data-3.f90: New test.