Add a test and bless existing test case.

Author: crlf0710

src/test/ui/codemap_tests/unicode_2.stderr

@@ -14,7 +14,7 @@ LL |     let _ = ("아あ", 1i42);
    |
    = help: valid widths are 8, 16, 32, 64 and 128
 
-error[E0425]: cannot find value `a̐é` in this scope
+error[E0425]: cannot find value `a̐é` in this scope
   --> $DIR/unicode_2.rs:6:13
    |
 LL |     let _ = a̐é;

src/test/ui/rfc-2457/idents-normalized.rs

@@ -0,0 +1,8 @@
+// check-pass
+#![feature(non_ascii_idents)]
+
+struct Résumé; // ['LATIN SMALL LETTER E WITH ACUTE']
+
+fn main() {
+    let _ = Résumé; // ['LATIN SMALL LETTER E', 'COMBINING ACUTE ACCENT']
+}