make ui test output patch compatible #41948

Author: cengiz-io

src/tools/compiletest/src/runtest.rs

@@ -2415,11 +2415,11 @@ actual:\n\
         println!("expected {}:\n{}\n", kind, expected);
         println!("diff of {}:\n", kind);
 
-        for diff in diff::lines(actual, expected) {
+        for diff in diff::lines(expected, actual) {
             match diff {
-                diff::Result::Left(l)    => println!("+{}", l),
+                diff::Result::Left(l)    => println!("-{}", l),
                 diff::Result::Both(l, _) => println!(" {}", l),
-                diff::Result::Right(r)   => println!("-{}", r),
+                diff::Result::Right(r)   => println!("+{}", r),
             }
         }