Don't GC sparks for CAFs
Don't GC sparks for CAFs

We can't tell whether the CAF is actually garbage or not.

(cherry picked from commit 23b73c97312e4d812812ed25a6396fff44d1da28)

GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc,GaloisInc/halvm-ghc