Fix TypeError in meshgrid

[KumoLiu]

Fixes #8251

Remove indexing="ij" will not affect anything since it's default behavior in torch.

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[KumoLiu]

/build

[KumoLiu]

/build

[KumoLiu]

/build

[mingxin-zheng]

The fix for older version of torch.meshgrid looks good to me!