Add static assertions to bevy_utils for compile-time checks (#11182)

# Objective

- We want to use `static_assertions` to perform precise compile time
checks at testing time. In this PR, we add those checks to make sure
that `EntityHashMap` and `PreHashMap` are `Clone` (and we replace the
more clumsy previous tests)
- Fixes #11181 

(will need to be rebased once
#11178 is merged)

---------

Co-authored-by: Charles Bournhonesque <cbournhonesque@snapchat.com>

crates/bevy_utils/Cargo.toml

@@ -23,6 +23,9 @@ thiserror = "1.0"
 nonmax = "0.5"
 smallvec = { version = "1.11", features = ["serde", "union", "const_generics"] }
 
+[dev-dependencies]
+static_assertions = "1.1.0"
+
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 getrandom = { version = "0.2.0", features = ["js"] }
 

crates/bevy_utils/src/lib.rs

@@ -419,18 +419,9 @@ macro_rules! detailed_trace {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use static_assertions::assert_impl_all;
 
-    #[test]
-    fn test_clone_entity_hash_map() {
-        let map = EntityHashMap::<u64, usize>::default();
-        // This should compile
-        let _ = map.clone();
-    }
-
-    #[test]
-    fn test_clone_pre_hash_map() {
-        let map = PreHashMap::<u64, usize>::default();
-        // This should compile
-        let _ = map.clone();
-    }
+    // Check that the HashMaps are Clone if the key/values are Clone
+    assert_impl_all!(EntityHashMap::<u64, usize>: Clone);
+    assert_impl_all!(PreHashMap::<u64, usize>: Clone);
 }