update tests to match error reporting

Author: Oliver Schneider

src/test/compile-fail/array_const_index-0.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 static a: &'static [i32] = &[];
-static b: i32 = (&a)[1]; //~ ERROR: constant indexing failed: array index out of bounds
+static b: i32 = (&a)[1]; //~ ERROR: array index out of bounds
+//~^ ERROR: constant indexing failed
 
 fn main() {}

src/test/compile-fail/const-array-oob.rs

@@ -9,7 +9,8 @@
 // except according to those terms.
 
 const FOO: [u32; 3] = [1, 2, 3];
-const BAR: u32 = FOO[5]; //~ ERROR constant indexing failed: array index out of bounds
+const BAR: u32 = FOO[5]; //~ ERROR array index out of bounds
+//~^ ERROR constant indexing failed
 
 fn main() {
     let _ = BAR;