Implement Binding#irb.

Author: nirvdrum

src/main/ruby/core/binding.rb

@@ -20,4 +20,9 @@ def local_variables
     Truffle.invoke_primitive(:local_variable_names, self).dup
   end
   Truffle::Graal.always_split(method(:local_variables))
+
+  def irb
+    require 'irb'
+    irb
+  end
 end