These JavaScript operators were special hacks to ensure that we always
operate on Smis for the magic for-in index variable, but this never
really worked in the OSR case, because the OsrValue for the index
variable didn't have the proper information (that we have for the
JSForInPrepare in the non-OSR case).

Now that we have loop induction variable analysis and binary operation
hints, we can just use JSLessThan and JSAdd instead with appropriate
Smi hints, which handle the OSR case by inserting Smi checks (that are
always true). Thanks to OSR deconstruction and loop peeling these Smi
checks will be hoisted so they don't hurt the OSR case too much.

Drive-by-change: Rename the ForInDone bytecode to ForInContinue, since
we have to lower it to JSLessThan to get the loop induction variable
goodness.

R=epertoso@chromium.org
BUG=v8:5267

Review-Url: https://codereview.chromium.org/2289613002
Cr-Commit-Position: refs/heads/master@{#38968}