Fix a merge conflict on main-next. (#627)

This PR fixes a conflict between #610 and #619. #610 added a string
cache to `TypeInfo` using `ObjectIdentifier` instances as keys. #619
added support for move-only types to `TypeInfo`. Due to
rdar://134276458, move-only types cannot be used with
`ObjectIdentifier`. This PR uses `UInt` instead until that issue can be
resolved in a future stdlib update.

### Checklist:

- [x] Code and documentation should follow the style of the [Style
Guide](https://github.com/apple/swift-testing/blob/main/Documentation/StyleGuide.md).
- [x] If public symbols are renamed or modified, DocC references should
be updated.

Author: grynspan

Sources/Testing/Parameterization/TypeInfo.swift

@@ -312,9 +312,7 @@ extension TypeInfo: Hashable {
   public static func ==(lhs: Self, rhs: Self) -> Bool {
     switch (lhs._kind, rhs._kind) {
     case let (.type(lhs), .type(rhs)):
-      // == and ObjectIdentifier do not support move-only metatypes, so compare
-      // the bits of the types directly. SEE: rdar://134276458
-      return unsafeBitCast(lhs, to: UnsafeRawPointer.self) == unsafeBitCast(rhs, to: UnsafeRawPointer.self)
+      return ObjectIdentifier(lhs) == ObjectIdentifier(rhs)
     default:
       return lhs.fullyQualifiedNameComponents == rhs.fullyQualifiedNameComponents
     }
@@ -325,6 +323,21 @@ extension TypeInfo: Hashable {
   }
 }
 
+// MARK: - ObjectIdentifier support
+
+extension ObjectIdentifier {
+  /// Initialize an instance of this type from a type reference.
+  ///
+  /// - Parameters:
+  ///   - type: The type to initialize this instance from.
+  ///
+  /// - Bug: The standard library should support this conversion.
+  ///   ([134276458](rdar://134276458), [134415960](rdar://134415960))
+  fileprivate init(_ type: any ~Copyable.Type) {
+    self.init(unsafeBitCast(type, to: Any.Type.self))
+  }
+}
+
 // MARK: - Codable
 
 extension TypeInfo: Codable {