[embedded] Provide alternate === and !== implementations instead of trying to switch away from existentials in a unified way

Author: kubamracek

stdlib/public/core/Equatable.swift

@@ -246,6 +246,19 @@ extension Equatable {
 /// - Parameters:
 ///   - lhs: A reference to compare.
 ///   - rhs: Another reference to compare.
+#if !$Embedded
+@inlinable // trivial-implementation
+public func === (lhs: AnyObject?, rhs: AnyObject?) -> Bool {
+  switch (lhs, rhs) {
+  case let (l?, r?):
+    return ObjectIdentifier(l) == ObjectIdentifier(r)
+  case (nil, nil):
+    return true
+  default:
+    return false
+  }
+}
+#else
 @inlinable // trivial-implementation
 public func ===<T: AnyObject, U: AnyObject>(lhs: T?, rhs: U?) -> Bool {
   switch (lhs, rhs) {
@@ -257,6 +270,7 @@ public func ===<T: AnyObject, U: AnyObject>(lhs: T?, rhs: U?) -> Bool {
     return false
   }
 }
+#endif
 
 /// Returns a Boolean value indicating whether two references point to
 /// different object instances.
@@ -268,9 +282,14 @@ public func ===<T: AnyObject, U: AnyObject>(lhs: T?, rhs: U?) -> Bool {
 /// - Parameters:
 ///   - lhs: A reference to compare.
 ///   - rhs: Another reference to compare.
+#if !$Embedded
+@inlinable // trivial-implementation
+public func !== (lhs: AnyObject?, rhs: AnyObject?) -> Bool {
+  return !(lhs === rhs)
+}
+#else
 @inlinable // trivial-implementation
 public func !==<T: AnyObject, U: AnyObject>(lhs: T, rhs: U) -> Bool {
   return !(lhs === rhs)
 }
-
-
+#endif