Disable the BackgroundCompileTask and CompilerDispatcher unittests when
--finalize-streaming-on-background is enabled. The inner function API to
concurrent compilation doesn't yet support off-thread finalization, so
these tests break under that configuration.

Bug: chromium:1011762
Change-Id: If8d8d8e814161668e12f309e8d69ef8e8a29ab4a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2502329
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70846}