Use closures more consistently in `dep_graph.rs`. This file has several methods that take a `FnOnce() -> R` closure: - `DepGraph::with_ignore` - `DepGraph::with_query_deserialization` - `DepGraph::with_anon_task` - `DepGraphData::with_anon_task_inner` It also has two methods that take a faux closure via an `A` argument and a `fn(TyCtxt<'tcx>, A) -> R` argument: - DepGraph::with_task - DepGraphData::with_task The rationale is that the faux closure exercises tight control over what state they have access to. This seems silly when (a) they are passed a `TyCtxt`, and (b) when similar nearby functions take real closures. And they are more awkward to use, e.g. requiring multiple arguments to be gathered into a tuple. This commit changes the faux closures to real closures. r? @Zalathar