test: Add a min-llvm-version directive

We've got tests which require a particular version of LLVM to run as they're
testing bug fixes. Our build system, however, supports multiple LLVM versions,
so we can't run these tests on all LLVM versions.

This adds a new `min-llvm-version` directive for tests so they can opt out of
being run on older versions of LLVM. This then namely applies that logic to the
`issue-36023.rs` test case and...

Closes #36138

src/test/run-pass/issue-36023.rs

@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+// min-llvm-version 3.9
+
 use std::ops::Deref;
 
 fn main() {