self compile time

[Stephen Weeks]

> > After fixing a performance bug in the match compiler and a nasty space leak that 
> > was basically slowing everything down (due to excess GC), 
> 
> Was this space leak the cause of the strange self compiles with the new
> contification pass?

"cause" may be a bit strong but it was certainly related, in that the problem
has now gone away that I have fixed the leak.  I am unable to concoct an
explanation why, though.