Switch multigpu runner (#2762)

Follows https://github.com/pytorch/pytorch/pull/105759/files

Old commits: 22min
This PR: 15min

Author: clee2000

.github/workflows/build-tutorials.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         include:
-          - { shard: 1, num_shards: 15, runner: "linux.16xlarge.nvidia.gpu" }
+          - { shard: 1, num_shards: 15, runner: "linux.g5.12xlarge.nvidia.gpu" }
           - { shard: 2, num_shards: 15, runner: "linux.g5.4xlarge.nvidia.gpu" }
           - { shard: 3, num_shards: 15, runner: "linux.g5.4xlarge.nvidia.gpu" }
           - { shard: 4, num_shards: 15, runner: "linux.g5.4xlarge.nvidia.gpu" }