For Divide operations like

  r = a / b

where r has only truncated uses (i.e. only used in bitwise operations),
we used to generate a Float64Div unless we statically knew something
about a and b, even if a and b have always been integers so far.
Crankshaft was able to generate an integer division here, because
Fullcodegen collected feedback independently for inputs and outputs of
binary operations.

This adds new BinaryOperationFeedback::kSignedSmallInputs, which is used
specifically for Divide to state that we have seen only SignedSmall
inputs thus far, but the outputs weren't always in the SignedSmall
range.

The issue was discovered in a WebGL Triangulation library and reported
via https://twitter.com/mourner/status/895708603117518848 after Node
8.3.0 was released with I+TF.

R=jarin@chromium.org

Bug: v8:6698
Change-Id: I830e421a3bf91fc8fa3665cbb706bc13675a6d2b
Reviewed-on: https://chromium-review.googlesource.com/612063
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47302}