Add ICE reproduction for issue rust-lang/rust#79666.

Author: rustbot

ices/79666.rs

@@ -0,0 +1,8 @@
+#![feature(const_generics)]
+#![feature(generic_associated_types)]
+
+trait A {
+    type B<const N: usize>;
+    
+    fn foo<const N: usize>(&self) -> Self::B<{N}>;
+}