[testing] Remove wrapper from @slow

[driazati]

trafficstars

This makes it a normal pytest decorator so it doesn't incur test set up / tear down. This also makes the PR body the source of truth for skipping slow tests or not since it can be confusing sourcing it both from the PR and commit message.

[github-actions[bot]]

Built docs for commit 5c6b52a0ed0b2a5580423d1be8efbf2cd1d1a42b can be found here.

[github-actions[bot]]

Built docs for commit ffb68fa105d822123845115565a0da336d4950fe can be found here.

[github-actions[bot]]

Built docs for commit 8fd7fd5df900ff424809dab2c5bfceab37c62d1f can be found here.

[driazati]

@tvm-bot rerun

[github-actions[bot]]

Built docs for commit 4c4248ea657a7e650a3517fac8eee79ded649cab can be found here.