[cleanup] Remove unactionable TODO

Liftoff is fully supported on all officially supported platforms, thus
remove a TODO to implement it on more platforms.

R=thibaudm@chromium.org

Bug: v8:11879
Change-Id: I00a559286d67e7e377a36b68803ee30e8fa2f34e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3168341
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76987}

test/mjsunit/mjsunit.status

@@ -1279,9 +1279,7 @@
 }], # arch != x64 or deopt_fuzzer
 
 ##############################################################################
-# Liftoff is currently only sufficiently implemented on x64, ia32, arm64,
-# arm, ppc64 and s390x.
-# TODO(clemensb): Implement on all other platforms (crbug.com/v8/6600).
+# Skip Liftoff tests on platforms that do not fully implement Liftoff.
 ['arch not in (x64, ia32, arm64, arm, ppc64, s390x)', {
   'wasm/liftoff': [SKIP],
   'wasm/liftoff-debug': [SKIP],
@@ -1290,7 +1288,7 @@
   'wasm/wasm-dynamic-tiering': [SKIP],
   'wasm/test-partial-serialization': [SKIP],
   'regress/wasm/regress-1248024': [SKIP],
-}], # arch not in (x64, ia32, arm64, arm, ppc64 and s390x)
+}], # arch not in (x64, ia32, arm64, arm, ppc64, s390x)
 
 ##############################################################################
 ['system != linux or virtual_memory_cage == True', {