rename isl_ast_build_ast_from_schedule to isl_ast_build_node_from_schedule_map
The original name turns out to have been a mistake since we would
like to introduce a parallel function that takes an isl_schedule
rather than an isl_union_map as input and the _schedule suffix
is already taken by this function.
We therefore rename the function to isl_ast_build_node_from_schedule_map
such that we can introduce a parallel isl_ast_build_node_from_schedule.
Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>