Bump to 1.31.0 and bootstrap from 1.30 beta

src/test/ui/issues/issue-42755.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![cfg_attr(stage0, feature(macro_vis_matcher))]
 
 macro_rules! foo {
     ($($p:vis)*) => {} //~ ERROR repetition matches empty token tree

src/test/ui/lint/unreachable_pub-pub_crate.rs

@@ -16,7 +16,6 @@
 
 // compile-pass
 
-#![cfg_attr(stage0, feature(macro_vis_matcher))]
 
 #![allow(unused)]
 #![warn(unreachable_pub)]

src/test/ui/lint/unreachable_pub.rs

@@ -11,7 +11,6 @@
 // compile-pass
 
 #![feature(crate_visibility_modifier)]
-#![cfg_attr(stage0, feature(macro_vis_matcher))]
 
 #![allow(unused)]
 #![warn(unreachable_pub)]