I bisected the performance difference in Haddock and found it was due to
d6aec63c009c4e57181900eb03847d7dc0fc3c7c, which I accidentally picked up
when updating Haddock 00b8f8c5

.  The
performance regression is justified by the fact that we are now actually
processing URLs in Haddock comments that we were not previously, so
there would be more allocation.  Time use was not affected.

The TODOs simply reflect the fact that we need updated numbers for
32-bit Linux and Windows.  Please add them when you get a chance.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>