Revert "Allow unused_labels in some compile-fail tests"

This reverts commit b9257e2ca161b1bf5aae9d6b667f4d0c6b8d7be6.

Author: kylestach

src/test/compile-fail/associated-types-outlives.rs

@@ -27,7 +27,6 @@ fn denormalise<'a, T>(t: &'a T) -> <T as Foo<'a>>::Bar {
 pub fn free_and_use<T: for<'a> Foo<'a>,
                     F: for<'a> FnOnce(<T as Foo<'a>>::Bar)>(x: T, f: F) {
     let y;
-    #[allow(unused_labels)]
     'body: loop { // lifetime annotations added for clarity
         's: loop { y = denormalise(&x); break }
         drop(x); //~ ERROR cannot move out of `x` because it is borrowed

src/test/compile-fail/hygienic-label-1.rs

@@ -13,6 +13,5 @@ macro_rules! foo {
 }
 
 pub fn main() {
-    #[allow(unused_labels)]
     'x: loop { foo!() }
 }

src/test/compile-fail/hygienic-label-2.rs

@@ -9,10 +9,7 @@
 // except according to those terms.
 
 macro_rules! foo {
-    ($e: expr) => {
-        #[allow(unused_labels)]
-        'x: loop { $e }
-    }
+    ($e: expr) => { 'x: loop { $e } }
 }
 
 pub fn main() {

src/test/compile-fail/hygienic-label-3.rs

@@ -13,7 +13,6 @@ macro_rules! foo {
 }
 
 pub fn main() {
-    #[allow(unused_labels)]
     'x: for _ in 0..1 {
         foo!()
     };

src/test/compile-fail/hygienic-label-4.rs

@@ -9,10 +9,7 @@
 // except according to those terms.
 
 macro_rules! foo {
-    ($e: expr) => {
-        #[allow(unused_labels)]
-        'x: for _ in 0..1 { $e }
-    }
+    ($e: expr) => { 'x: for _ in 0..1 { $e } }
 }
 
 pub fn main() {

src/test/compile-fail/issue-27042.rs

@@ -10,7 +10,6 @@
 
 // Regression test for #27042. Test that a loop's label is included in its span.
 
-#[allow(unused_labels)]
 fn main() {
     let _: i32 =
         'a: // in this case, the citation is just the `break`:

src/test/compile-fail/issue-46311.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 fn main() {
-    #[allow(unused_labels)]
     'break: loop { //~ ERROR invalid label name `'break`
     }
 }

src/test/compile-fail/loop-break-value.rs

@@ -77,7 +77,6 @@ fn main() {
     }
 
     let _: i32 = 'a: loop {
-        #[allow(unused_labels)]
         let _: () = 'b: loop {
             break ('c: loop {
                 break;

src/test/compile-fail/loop-proper-liveness.rs

@@ -32,7 +32,6 @@ fn test2() {
 fn test3() {
     let x: i32;
     // Similarly, the use of variable `x` is unreachable.
-    #[allow(unused_labels)]
     'a: loop {
         x = loop { return };
     }

src/test/compile-fail/resolve-label.rs

@@ -8,7 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#[allow(unused_labels)]
 fn f() {
     'l: loop {
         fn g() {