Make most tests an example so we can run them one by one

tests/ui/unicode.rs

@@ -1,26 +0,0 @@
-#![feature(plugin)]
-#![plugin(clippy)]
-
-#[deny(zero_width_space)]
-fn zero() {
-    print!("Here >​< is a ZWS, and ​another");
-    print!("This\u{200B}is\u{200B}fine");
-}
-
-#[deny(unicode_not_nfc)]
-fn canon() {
-    print!("̀àh?");
-    print!("a\u{0300}h?"); // also okay
-}
-
-#[deny(non_ascii_literal)]
-fn uni() {
-    print!("Üben!");
-    print!("\u{DC}ben!"); // this is okay
-}
-
-fn main() {
-    zero();
-    uni();
-    canon();
-}