Reland "[cctest] Add fuzz tests for generating parallel moves."

This is a reland of c6b153fd
Original change's description:
> [cctest] Add fuzz tests for generating parallel moves.
>
> These new tests are somewhat similar to the existing gap resolver tests except
> we use the code generator and eventually run the generated code. The main idea
> is to cover cases that are difficult to hit, such as move from/to slots which
> are out of range of loads and stores, but may happen nonetheless.
>
> At this time, the tests only make sure the code generator actually generated
> some code, and that this code runs. In the future, it would be great to also
> check that the moves were actually performed.
>
> Bug: v8:6553
> Change-Id: I089a25fa05b3a20649658bb8952926ab11f91d68
> Reviewed-on: https://chromium-review.googlesource.com/574850
> Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
> Reviewed-by: Bill Budge <bbudge@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#47733}

Bug: v8:6553
Change-Id: Ia3eac9d7e6a23e2f6fea839b71d460cb7ad6ff6e
Reviewed-on: https://chromium-review.googlesource.com/645868Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Pierre Langlois <pierre.langlois@arm.com>
Cr-Commit-Position: refs/heads/master@{#48115}