Make HandleCycleError an enum instead of a macro-generated closure

- Add a `HandleCycleError` enum to rustc_query_system, along with a `handle_cycle_error` function
- Move `Value` to rustc_query_system, so `handle_cycle_error` can use it
- Move the `Value` impls from rustc_query_impl to rustc_middle. This is necessary due to orphan rules.

compiler/rustc_query_system/src/error.rs

@@ -12,6 +12,13 @@ impl AddSubdiagnostic for CycleStack {
     }
 }
 
+#[derive(Copy, Clone)]
+pub enum HandleCycleError {
+    Error,
+    Fatal,
+    DelayBug,
+}
+
 #[derive(SessionSubdiagnostic)]
 pub enum StackCount {
     #[note(query_system::cycle_stack_single)]