Fix fallout in tests.

Author: jseyfried

src/test/compile-fail/issue-21146.rs

@@ -8,6 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern: expected item, found `parse_error`
+// error-pattern: expected one of `!` or `::`, found `<eof>`
 include!("auxiliary/issue-21146-inc.rs");
 fn main() {}

src/test/compile-fail/macro-context.rs

@@ -14,11 +14,8 @@ macro_rules! m {
                             //~| ERROR macro expansion ignores token `typeof`
                             //~| ERROR macro expansion ignores token `;`
                             //~| ERROR macro expansion ignores token `;`
-                            //~| ERROR macro expansion ignores token `i`
 }
 
-m!();               //~ NOTE the usage of `m!` is likely invalid in item context
-
 fn main() {
     let a: m!();    //~ NOTE the usage of `m!` is likely invalid in type context
     let i = m!();   //~ NOTE the usage of `m!` is likely invalid in expression context

src/test/compile-fail/self_type_keyword.rs

@@ -30,8 +30,7 @@ pub fn main() {
         ref mut Self => (),
         //~^ ERROR expected identifier, found keyword `Self`
         Self!() => (),
-        //~^ ERROR expected identifier, found keyword `Self`
-        //~^^ ERROR macro undefined: 'Self!'
+        //~^ ERROR macro undefined: 'Self!'
         Foo { x: Self } => (),
         //~^ ERROR expected identifier, found keyword `Self`
         Foo { Self } => (),

src/test/parse-fail/extern-no-fn.rs

@@ -11,7 +11,7 @@
 // compile-flags: -Z parse-only
 
 extern {
-    f(); //~ ERROR expected one of `fn`, `pub`, `static`, or `}`, found `f`
+    f(); //~ ERROR expected one of `!` or `::`, found `(`
 }
 
 fn main() {

src/test/parse-fail/issue-21153.rs

@@ -11,5 +11,6 @@
 // compile-flags: -Z parse-only
 
 trait MyTrait<T>: Iterator {
-    Item = T; //~ ERROR expected one of `const`, `extern`, `fn`, `type`, or `unsafe`, found `Item`
+    Item = T; //~ ERROR expected one of `!` or `::`, found `=`
+              //~| ERROR expected item, found `=`
 }