Indexing ops should support unsigned integer types

[AndrewZhaoLuo]

Right now stuff like gather, take, gather_nd, scatter are bound to signed integers. This should be pretty simple to add, we just need to change the type relations to support, most of the topi should work out of box.

Portions of #10053 apply insight into how to do this.

List of ops:

• gather (@AndrewZhaoLuo)
• gather_nd (@AndrewZhaoLuo)
• take (@AndrewZhaoLuo)
• scatter (@FZYUAN-1)
• scatter_add (@FZYUAN-1)
• scatter_nd (@FZYUAN-1)
• unravel_index (@FZYUAN-1)
• adv_index (@FZYUAN-1)

[yuanfz98]

Hello @AndrewZhaoLuo,

Can I take the last 5 ops (scatter, scatter_add, scatter_nd, unravel_index, adv_index)?

[AndrewZhaoLuo]

Yeah sure, thanks for the help B)