Doubling number of shards for test262 novfp3 on arm sim debug

Bug: v8:12538
Change-Id: I89e7fcde7226d680f3385f527cb2e456829a476d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3376962Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Almothana Athamneh <almuthanna@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78530}

infra/testing/builders.pyl

@@ -1836,7 +1836,8 @@
         'name': 'test262',
         'suffix': 'novfp3',
         'variant': 'default',
-        'test_args': ['--novfp3']
+        'test_args': ['--novfp3'],
+        'shards': 2
       },
       {
         'name': 'v8testing',