This CL adds decoding and code generation for the table.size
instruction.

R=mstarzinger@chromium.org

Bug: v8:7581
Change-Id: I0e689a993d25db72281ebba0854454be12f4d350
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1593302
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61195}