Since Liftoff is fully implemented on arm64, we can enable the
wasm/liftoff test.

R=ahaas@chromium.org

Bug: v8:6600
Change-Id: I901480a417a7cc438357a67b819f226e4d3b1df4
Reviewed-on: https://chromium-review.googlesource.com/1134776
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54417}