updates to compile-fail tests for changes to NLL.

Author: pnkfelix

src/test/compile-fail/borrowck/borrowck-issue-14498.rs

@@ -27,7 +27,7 @@ fn indirect_write_to_imm_box() {
     let y: Box<_> = box &mut x;
     let p = &y;
     ***p = 2; //[ast]~ ERROR cannot assign to data in a `&` reference
-              //[mir]~^ ERROR cannot assign to data in a `&` reference
+              //[mir]~^ ERROR cannot assign to `***p`
     drop(p);
 }
 

src/test/compile-fail/borrowck/borrowck-overloaded-index-ref-index.rs

@@ -70,6 +70,6 @@ fn main() {
     };
     s[2] = 20;
     //[ast]~^ ERROR cannot assign to immutable indexed content
-    //[mir]~^^ ERROR cannot assign to immutable item
+    //[mir]~^^ ERROR cannot assign to data in a `&` reference
     drop(rs);
 }

src/test/compile-fail/unboxed-closures-mutated-upvar-from-fn-closure.rs

@@ -23,6 +23,6 @@ fn main() {
     call(|| {
         counter += 1;
         //[ast]~^ ERROR cannot assign to data in a captured outer variable in an `Fn` closure
-        //[mir]~^^ ERROR cannot assign to immutable item `counter`
+        //[mir]~^^ ERROR cannot assign to `counter`
     });
 }