[test] Bump shards on slow arm64 trybot

Also skip slowest test on the slowest extra variant.

TBR=sigurds@chromium.org

Bug: v8:7783
Change-Id: I565fa8edd9c3f20fe15af84e1b9023450ef4593e
Reviewed-on: https://chromium-review.googlesource.com/1170832
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55053}

infra/testing/builders.pyl

@@ -267,7 +267,7 @@
       {'name': 'mozilla'},
       {'name': 'test262'},
       {'name': 'v8testing', 'shards': 9},
-      {'name': 'v8testing', 'variant': 'extra', 'shards': 3},
+      {'name': 'v8testing', 'variant': 'extra', 'shards': 4},
     ],
   },
   ##############################################################################

test/webkit/webkit.status

@@ -116,10 +116,10 @@
 }],  # arch == arm64 and msan
 
 ##############################################################################
-['(variant == nooptimization or variant == stress) and (arch == arm or arch == arm64) and simulator_run', {
+['(variant == nooptimization or variant == stress or variant == no_liftoff) and (arch == arm or arch == arm64) and simulator_run', {
   # Slow tests: https://crbug.com/v8/7783
   'dfg-double-vote-fuzz': [SKIP],
-}],  # (variant == nooptimization or variant == stress) and (arch == arm or arch == arm64) and simulator_run
+}],  # (variant == nooptimization or variant == stress or variant == no_liftoff) and (arch == arm or arch == arm64) and simulator_run
 
 ##############################################################################
 ['gcov_coverage', {