Rollup merge of #144358 - JonathanBrouwer:fix-stability-malformed, r=oli-obk

Stop using the old `validate_attr` logic for stability attributes

I think this was accidentally missed when implementing the stability attributes?

r? `````@oli-obk`````
cc `````@jdonszelmann`````

compiler/rustc_attr_parsing/src/attributes/stability.rs

@@ -74,8 +74,15 @@ impl<S: Stage> AttributeParser<S> for StabilityParser {
             template!(NameValueStr: "deprecation message"),
             |this, cx, args| {
                 reject_outside_std!(cx);
-                this.allowed_through_unstable_modules =
-                    args.name_value().and_then(|i| i.value_as_str())
+                let Some(nv) = args.name_value() else {
+                    cx.expected_name_value(cx.attr_span, None);
+                    return;
+                };
+                let Some(value_str) = nv.value_as_str() else {
+                    cx.expected_string_literal(nv.value_span, Some(nv.value_as_lit()));
+                    return;
+                };
+                this.allowed_through_unstable_modules = Some(value_str);
             },
         ),
     ];
@@ -247,7 +254,12 @@ pub(crate) fn parse_stability<S: Stage>(
     let mut feature = None;
     let mut since = None;
 
-    for param in args.list()?.mixed() {
+    let ArgParser::List(list) = args else {
+        cx.expected_list(cx.attr_span);
+        return None;
+    };
+
+    for param in list.mixed() {
         let param_span = param.span();
         let Some(param) = param.meta_item() else {
             cx.emit_err(session_diagnostics::UnsupportedLiteral {
@@ -322,7 +334,13 @@ pub(crate) fn parse_unstability<S: Stage>(
     let mut is_soft = false;
     let mut implied_by = None;
     let mut old_name = None;
-    for param in args.list()?.mixed() {
+
+    let ArgParser::List(list) = args else {
+        cx.expected_list(cx.attr_span);
+        return None;
+    };
+
+    for param in list.mixed() {
         let Some(param) = param.meta_item() else {
             cx.emit_err(session_diagnostics::UnsupportedLiteral {
                 span: param.span(),