Because the typeof operator may lower to a builtin call (which is
effectful in turbofan parlance after effect control linearization),
it really should be encoded as a simplified operator, which can
be optimized with respect for the effect chain in linearization.

No new functionality here, rather a furniture rearrangement in
the TurboFan node structure.

BUG=v8:6929

Change-Id: I38593e10956ebd57cecdd606c35f3f73efb1327e
Reviewed-on: https://chromium-review.googlesource.com/718745Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48613}