We use the new V9 FXTOD instruction to convert Longs to Doubles. This is performance-broken by a factor of 1000 for sufficiently large longs, which leads to a factor of 1000 slowdown between server vs client for random->double heavy codes.

Run the attached file on both a U2 and a U3 to check out the speed problem.

Re-enable for U2's when bug 4453420 is fixed.