Rollup merge of #144429 - Gelbpunkt:outline-atomics-aarch64-musl, r=Amanieu

Enable outline-atomics for aarch64-unknown-linux-musl

They were disabled in bd287fa and haven't been causing problems for a while anymore, see #89626 for details.

The entire testsuite still passes on `aarch64-unknown-linux-musl` with this feature enabled.

Author: jhpratt

compiler/rustc_target/src/spec/targets/aarch64_unknown_linux_musl.rs

@@ -6,7 +6,7 @@ pub(crate) fn target() -> Target {
     let mut base = base::linux_musl::opts();
     base.max_atomic_width = Some(128);
     base.supports_xray = true;
-    base.features = "+v8a".into();
+    base.features = "+v8a,+outline-atomics".into();
     base.stack_probes = StackProbeType::Inline;
     base.supported_sanitizers = SanitizerSet::ADDRESS
         | SanitizerSet::CFI