File.new (and related paths) unconditionally calling to_int on first arg

# From https://github.com/rspec/rspec-core/issues/195 
# and patched (unsuccessfully on JRuby) in https://github.com/rspec/rspec-core/issues/295

String.send :alias_method, :to_int, :to_i

puts File.readlines(__FILE__).empty? # is false on 1.8 and 1.9, true on JRuby 1.6.0

diff --git a/src/org/jruby/RubyFile.java b/src/org/jruby/RubyFile.java
index ae5d8e3..e50268b 100755
--- a/src/org/jruby/RubyFile.java
+++ b/src/org/jruby/RubyFile.java
@@ -424,10 +424,8 @@ public class RubyFile extends RubyIO implements EncodingCapable {
         }
         
         if (args.length > 0 && args.length < 3) {
-            IRubyObject fd = TypeConverter.convertToTypeWithCheck(args[0], getRuntime().getFixnum(), "to_int");
-            if (!fd.isNil()) {
-                args[0] = fd;
-                return super.initialize(args, block);
+            if (args[0] instanceof RubyInteger) {
+                return super.initialize(new IRubyObject[] {args[0]}, block);
             }
         }