Instead of de-sugaring destructuring assignment in the parser (using the
pattern rewriter), pass the Object/ArrayLiterals through to the bytecode
generator, which can desugar them in-place.

This allows us to decrease the amount of AST node creation, and improve
the generated bytecode using domain-specific knowledge. As a side effect
we partially fix an old execution ordering spec bug.

Currently only implemented for assignments, not declarations, as the
latter has some additional complexity.

Bug: v8:4951
Change-Id: I3d69d232bea2968ef20df68a74014d9e05808cfe
Reviewed-on: https://chromium-review.googlesource.com/c/1375660
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58512}