Rollup merge of #125215 - Oneirical:easy-test-the-second, r=jieyouxu

Migrate `run-make/issue64319` to `rmake` and rename

Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).

~~I noticed that the Makefile was not listed in `allowed-run-makefiles` in Tidy. Does this mean the test was being ignored?~~ EDIT: No, it was there, just not in its expected alphabetical order.

EDIT2: Perhaps it could be interesting to clean this test visually by looping over the `rustc` calls, like in #125227.

src/tools/run-make-support/src/rustc.rs

@@ -64,6 +64,12 @@ impl Rustc {
         self
     }
 
+    /// Specify a specific optimization level.
+    pub fn opt_level(&mut self, option: &str) -> &mut Self {
+        self.cmd.arg(format!("-Copt-level={option}"));
+        self
+    }
+
     /// Specify type(s) of output files to generate.
     pub fn emit(&mut self, kinds: &str) -> &mut Self {
         self.cmd.arg(format!("--emit={kinds}"));

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -128,7 +128,6 @@ run-make/issue-85401-static-mir/Makefile
 run-make/issue-85441/Makefile
 run-make/issue-88756-default-output/Makefile
 run-make/issue-97463-abi-param-passing/Makefile
-run-make/issue64319/Makefile
 run-make/jobserver-error/Makefile
 run-make/libs-through-symlinks/Makefile
 run-make/libtest-json/Makefile