Increase shards for test262 on V8 Linux64 - debug

Change-Id: I47ff2062a8f9fbb52f1760a47ebfdc0d2c035900
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3400963
Auto-Submit: Almothana Athamneh <almuthanna@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78680}

infra/testing/builders.pyl

@@ -1201,7 +1201,7 @@
       {'name': 'mozilla'},
       {'name': 'mozilla', 'variant': 'extra'},
       {'name': 'optimize_for_size'},
-      {'name': 'test262', 'shards': 5},
+      {'name': 'test262', 'shards': 7},
       {'name': 'test262', 'variant': 'extra', 'shards': 5},
       {'name': 'v8testing', 'shards': 2},
       {'name': 'v8testing', 'variant': 'extra', 'shards': 2},