... and update the list of unused bytecodes.

This CL also drops kInternalReferenceEncoded as all necessary details
are already encoded in RelocInfo.

Bug: v8:8794, v8:8562
Change-Id: Ia8aec1f4bcf9802fe15322bd6bb273218d8959fa
Reviewed-on: https://chromium-review.googlesource.com/c/1460459
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59471}