This is the first in a series of changes to reduce the number of
bytecodes generated for the iteration protocol based operations.
The GetIterator bytecode introduced in this change currently loads the
@@iterator symbol from an object that was previously done using the
LdaNamedProperty bytecode. This change uses builtin-based mechanism
that would be extended to perform additional operations in the future
on absorbing the bytecodes associated with the GetIterator operation
from the iteration protocol.

Bug: v8:9489
Change-Id: I83b8b55c27bae8260bf227f355eeca1ba80cd8f0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1701852
Commit-Queue: Swapnil Gaikwad <swapnilgaikwad@google.com>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63139}