10 argument variant of `Time.local` mishandles timezone.

The 10 argument variant of `Time.local` mishandles the timezone of the created object:

<pre>
JRuby:
(rdb:1) p Time.local(59, 59, 23, 31, 3, 2011, 4, 90, true, "PDT")
2011-03-31 23:59:59 UTC

MRI 1.9.3:
(rdb:1) p Time.local(59, 59, 23, 31, 3, 2011, 4, 90, true, "PDT")
2011-03-31 23:59:59 -0700
</pre>


This is present in 1.6.7.2, and also in 1.7.0.preview1
