Replace 0x16 with 0x18 for the delegate opcode, to avoid a conflict with
the function reference proposal.
See https://github.com/WebAssembly/exception-handling/issues/145

R=clemensb@chromium.org

Bug: v8:8091
Change-Id: Ib012f8680dfece200973e18fdf6c82877f10d5de
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2632604Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72118}