Fill in def_span when creating def ids.

This makes sure that ICEing because of def ids created outside of ast lowering will be able to produce a query backtrace and not cause a double panic because of trying to call the  `def_span` query

compiler/rustc_ast_lowering/src/expr.rs

@@ -365,7 +365,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let node_id = self.next_node_id();
 
                 // Add a definition for the in-band const def.
-                self.create_def(parent_def_id.def_id, node_id, DefPathData::AnonConst);
+                self.create_def(parent_def_id.def_id, node_id, DefPathData::AnonConst, f.span);
 
                 let anon_const = AnonConst { id: node_id, value: arg };
                 generic_args.push(AngleBracketedArg::Arg(GenericArg::Const(anon_const)));