Prevent stats being enabled late at run-time

yjit.rb

@@ -138,10 +138,6 @@ module YJIT
     Primitive.cexpr! 'rb_yjit_opts.gen_stats ? Qtrue : Qfalse'
   end
 
-  def self.stats_enabled=(enabled)
-    Primitive.set_stats_enabled(enabled)
-  end
-
   def self.enabled?
     Primitive.cexpr! 'rb_yjit_enabled_p() ? Qtrue : Qfalse'
   end

yjit_iface.c

@@ -811,13 +811,6 @@ reset_stats_bang(rb_execution_context_t *ec, VALUE self)
     return Qnil;
 }
 
-static VALUE
-set_stats_enabled(rb_execution_context_t *ec, VALUE self, VALUE enabled)
-{
-    rb_yjit_opts.gen_stats = RB_TEST(enabled);
-    return enabled;
-}
-
 #include "yjit.rbinc"
 
 #if YJIT_STATS