[Liftoff] Enable liftoff test on arm64

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}

test/mjsunit/mjsunit.status

@@ -821,12 +821,12 @@
 }], # arch != x64 or deopt_fuzzer
 
 ##############################################################################
-# Liftoff is currently only sufficiently implemented on x64 and ia32.
+# Liftoff is currently only sufficiently implemented on x64, ia32 and arm64.
 # TODO(clemensh): Implement on all other platforms (crbug.com/v8/6600).
-['arch != x64 and arch != ia32', {
+['arch != x64 and arch != ia32 and arch != arm64', {
   'wasm/liftoff': [SKIP],
   'wasm/tier-up-testing-flag': [SKIP],
-}], # arch != x64 and arch != ia32
+}], # arch != x64 and arch != ia32 and arch != arm64
 
 ##############################################################################
 ['variant == slow_path and gc_stress', {