fix some broken tests

Author: nikomatsakis

src/test/compile-fail/coercion-slice.rs

@@ -14,6 +14,6 @@ fn main() {
     let _: &[i32] = [0];
     //~^ ERROR mismatched types
     //~| expected type `&[i32]`
-    //~| found type `[i32; 1]`
+    //~| found type `[{integer}; 1]`
     //~| expected &[i32], found array of 1 elements
 }

src/test/compile-fail/cross-borrow-trait.rs

@@ -22,5 +22,4 @@ pub fn main() {
                         //~| expected type `&Trait`
                         //~| found type `Box<Trait>`
                         //~| expected &Trait, found box
-                        //~^^^^ ERROR E0277
 }

src/test/compile-fail/dst-bad-coercions.rs

@@ -23,13 +23,11 @@ pub fn main() {
     let x: *const S = &S;
     let y: &S = x; //~ ERROR mismatched types
     let y: &T = x; //~ ERROR mismatched types
-                   //~^ ERROR E0277
 
     // Test that we cannot convert from *-ptr to &S and &T (mut version)
     let x: *mut S = &mut S;
     let y: &S = x; //~ ERROR mismatched types
     let y: &T = x; //~ ERROR mismatched types
-                   //~^ ERROR E0277
 
     // Test that we cannot convert an immutable ptr to a mutable one using *-ptrs
     let x: &mut T = &S; //~ ERROR mismatched types

src/test/compile-fail/issue-13058.rs

@@ -36,5 +36,4 @@ fn check<'r, I: Iterator<Item=usize>, T: Itble<'r, usize, I>>(cont: &T) -> bool
 fn main() {
     check((3, 5));
 //~^ ERROR mismatched types
-//~| HELP try with `&(3, 5)`
 }