[CQ] Experiment to speed up the asan builder

No-Try: true
Bug: v8:11428
Change-Id: Ia06f5a99f851325103ad1860bf44a7313ea541f7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3581723Reviewed-by: Almothana Athamneh <almuthanna@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/main@{#79988}

infra/testing/builders.pyl

@@ -314,9 +314,9 @@
       'os': 'Ubuntu-18.04',
     },
     'tests': [
-      {'name': 'test262', 'shards': 7},
-      {'name': 'v8testing', 'shards': 3},
-      {'name': 'v8testing', 'variant': 'extra', 'shards': 3},
+      {'name': 'test262', 'shards': 12},
+      {'name': 'v8testing', 'shards': 5},
+      {'name': 'v8testing', 'variant': 'extra', 'shards': 5},
       {'name': 'v8testing', 'variant': 'slow_path'},
     ],
   },