Drop identityEquals from builtins, compiler and tests.

core/builtins/native/kotlin/Library.kt

@@ -16,13 +16,6 @@
 
 package kotlin
 
-/**
- * Returns true if the receiver and the [other] object are the same object instance, or if they
- * are both null.
- */
-@Deprecated("This function is deprecated, use === instead", ReplaceWith("this === other"))
-public fun Any?.identityEquals(other: Any?): Boolean // = this === other
-
 /**
  * Returns a string representation of the object. Can be called with a null receiver, in which case
  * it returns the string "null".