Ruby

Fix memory leak in ruby_parser

For example:

10.times do 100_000.times do eval("") end puts `ps -o rss= -p #{$$}` end 

Before:

19872 26480 32848 39504 45904 52672 59200 65760 72128 78496 

After:

17328 20752 23664 28400 30656 34224 37424 40784 43328 46656