This CL changes SharedFunctionInfo::GetBytecodeArray to a function
template, which is specialized for Isolate and LocalIsolate arguments.
This allows main thread only uses to avoid taking a lock.

Bug: v8:7790, chromium:1154603
Change-Id: I3462c4e36b66073e09393c01c765dd8a018a98f0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2595307
Commit-Queue: Nico Hartmann <nicohartmann@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71833}