[xmonad] runOrRaiseNext lost functionality in xmonad 0.9?

[Joseph Garvin]

I used to have the following line in my xmonad.hs to bind Win+F to
either open a new firefox or switch to an existing one in a way that
would work across multiple Ubuntu versions:

((modMask,  xK_f), runOrRaiseNext "firefox-3.5 || firefox3 || firefox"
(className =? "Firefox" <||> className =? "Shiretoko"))

The ||'s would be interpreted by the shell, first trying firefox-3.5,
then if it didn't work firefox3, etc. This worked great. But upgrading
to xmonad 0.9.1-2 (installed Lucid Lynx) this functionality broke. Now
nothing happens when I press Win+F, and I receive no errors.

If I just put "firefox" then it works, but "firefox || firefox" does
not, leading me to believe the command is no longer executed through
the shell. Is this intentional? If it is, is there a way that xmonad
provides for me to query what's in $PATH so I can bind the right
version of firefox?