Simplify static_assert_sizes.

We want to run them on all 64-bit platforms.

compiler/rustc_ast/src/ast.rs

@@ -3363,7 +3363,7 @@ impl TryFrom<ItemKind> for ForeignItemKind {
 pub type ForeignItem = Item<ForeignItemKind>;
 
 // Some nodes are used a lot. Make sure they don't unintentionally get bigger.
-#[cfg(all(any(target_arch = "x86_64", target_arch = "aarch64"), target_pointer_width = "64"))]
+#[cfg(target_pointer_width = "64")]
 mod size_asserts {
     use super::*;
     use rustc_data_structures::static_assert_size;