- use a token-range to quickly identify LHS continuation
- queue binding pattern errors only once
- outline LHS continuation to reduce memory overhead from aggressive inlining (30kb)

Change-Id: Ic0f3cfc3ea0bd6cedb6cea991a69f55f2bada14a
Reviewed-on: https://chromium-review.googlesource.com/c/1280207
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56633}