Remove Servo window.trap() extension (#30743)

This Servo-specific extension is unused by any code in the repository
and removing it allows us to remove use of nightly only reliance on
rust intrinsics. This is a step toward supporting stable rust.

components/script/dom/window.rs

@@ -1102,11 +1102,6 @@ impl WindowMethods for Window {
         }
     }
 
-    #[allow(unsafe_code)]
-    fn Trap(&self) {
-        unsafe { ::std::intrinsics::breakpoint() }
-    }
-
     #[allow(unsafe_code)]
     fn Js_backtrace(&self) {
         unsafe {