In the 'extra' variant, replace turboprop_as_toptier (which is mostly
covered by turboprop) with always_sparkplug, to increase Sparkplug's
coverage on tests.

Bug: v8:11420
Change-Id: I43b7009d184a03cb163d78f1f8bd05233ef7c34e
Fixed: v8:11686
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2862769
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74324}