This is a followup of the cl [1] that fixes a bug where bytecode was
getting flushed when allocating feedback vector. The fix added
IsCompiledScope before allocating a new feedback vector. We now pass
IsCompiledScope to JSFunction::EnsureFeedbackVector. This makes it
explicit that EnsureFeedbackVector expects a function that is compiled
and the bytecode shouldn't be flushed during the allocation.Also adds
a test.


[1] https://chromium-review.googlesource.com/c/v8/v8/+/2218066

Bug: v8:10560
Change-Id: I552c449a57555dffa625b2e4efa04c2c276fc0b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2222347
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68142}