Revert "Temporarily failing test in uefi-macros"

This reverts commit a4f4fd2. The
upstream issue that was causing these tests to fail has been fixed:
rust-lang/rust#89795

Fixes #299

Author: nicholasbishop

uefi-macros/tests/compilation.rs

@@ -1,7 +1,6 @@
 use std::env;
 
 #[test]
-#[ignore = "failing in nightly due to github.com/rust-lang/rust/issues/89795"]
 fn ui() {
     let t = trybuild::TestCases::new();