Update compile-fail tests due to changed diagnostics

Author: bkoropoff

src/test/compile-fail/resolve-conflict-import-vs-extern-crate.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use std::slice as std; //~ ERROR import conflicts with imported crate
+use std::slice as std; //~ ERROR import `std` conflicts with imported crate
 
 fn main() {
 }

src/test/compile-fail/resolve-conflict-item-vs-import.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 use std::mem::transmute;
-//~^ ERROR import conflicts with value in this module
+//~^ ERROR import `transmute` conflicts with value in this module
 
 fn transmute() {}