Add Numeric#clone method to return self, remove initalize_copy

Author: bjfish

CHANGELOG.md

@@ -39,6 +39,7 @@ Bug fixes:
 * `Kernel#sprintf` encoding validity has been fixed (#1852, @XrXr).
 * Fixed File.fnmatch causes ArrayIndexOutOfBoundsException (#1845).
 * Make `String#concat` work with no or multiple arguments (#1519).
+* Implement Numeric#clone method to return self.
 
 Compatibility:
 

spec/tags/core/kernel/clone_tags.txt

@@ -3,5 +3,3 @@ fails:Kernel#clone returns true for TrueClass
 fails:Kernel#clone returns false for FalseClass
 fails:Kernel#clone returns the same Integer for Integer
 fails:Kernel#clone returns the same Symbol for Symbol
-fails:Kernel#clone returns self for Complex
-fails:Kernel#clone returns self for Rational

src/main/ruby/truffleruby/core/numeric.rb

@@ -29,9 +29,11 @@
 class Numeric
   include Comparable
 
-  # Always raises TypeError, as dup'ing Numerics is not allowed.
-  def initialize_copy(other)
-    raise TypeError, "copy of #{self.class} is not allowed"
+  def clone(freeze: true)
+    unless freeze
+      raise ArgumentError, "can't unfreeze #{self.class.name}"
+    end
+    self
   end
 
   def +@