This wraps float arrays with a proxy to make raw buffer use slow paths avoiding different NAN patterns.

This also mocks out large typed arrays when passing the lenth as third constructor parameter.

BUG=chromium:691287,chromium:690898
NOTRY=true

Change-Id: Ic4295b0d8690e5209aceeda9ed93efdd580194c0
Reviewed-on: https://chromium-review.googlesource.com/441624
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#43229}