Convert negative indices to unsigned when static tensor shapes are available

[brandonwillard]

One thing we could also explore (separately) is converting constant negative indexes to positive indexes when the shape of the tensor is fixed. We know this at the Aesara level, but not necessarily after compilation.

Originally posted by @ricardoV94 in https://github.com/aesara-devs/aesara/issues/1150#issuecomment-1229222356