[platform] Do not use current_platform in global namespace

[wangxiyuan]

Once platform pluggable supported, use current_platform in global namespace is dangerous. Because it's hard to guarantee that current_platform is initialized correctly when it's used in global namespace. It'll lead unexpected problem and is hard to debug.

This PR drop the current_platform usage in global namespace in most place.

There is a place which will be fixed in next PR for easier review.

• HAS_TRITON

[github-actions]

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[wangxiyuan]

No need now, see: #11602