[infra] Increase timeout (1h → 2h) and bump shards (8 → 10) due to lower performance bots (8 → 4 cpus)

Bug: chromium:1279426
Change-Id: I6e4d010ae57541b051529a76b11d265d34f36010
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3350579
Auto-Submit: Alexander Schulze <alexschulze@chromium.org>
Reviewed-by: Liviu Rau <liviurau@chromium.org>
Commit-Queue: Liviu Rau <liviurau@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78423}