[Feature: trunk] GC.stat

$B%A%1%C%H(B #1628 $B$,99?7$5$l$^$7$?!#(B (by Koichi Sasada)

$B%9%F!<%?%9(B Assigned$B$+$i(BClosed$B$KJQ99(B
$B?JD=(B % 0$B$+$i(B100$B$KJQ99(B

This issue was solved with changeset r29616.
Koichi, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.