fix: Ensure Guard's drop method is removed at opt-level=s for Copy types

Added `#[inline]` to the `drop` method in the `Guard` implementation to ensure that the method is removed by the compiler at optimization level `opt-level=s` for `Copy` types. This change aims to align the method's behavior with optimization expectations and ensure it does not affect performance.

Author: cblh

library/core/src/array/mod.rs

@@ -889,6 +889,7 @@ impl<T> Guard<'_, T> {
 }
 
 impl<T> Drop for Guard<'_, T> {
+    #[inline]
     fn drop(&mut self) {
         debug_assert!(self.initialized <= self.array_mut.len());