Check validity of new access relations. NFC.

Check validity of new access relations. NFC.

There are some constraints on maps that can be access relations. In builds with assertions enabled, verify

  - The access domain is the same space as the statement's domain (modulo parameters).
  - Whether an access is defined for every instance of the statement. (codegen does not yet support partial access relations)
  - Whether the access range links to an array, represented by a ScopArrayInfo.
  - The number of access dimensions equals the dimensions of the array.
  - The array is not an indirect access. (also not supported by codegen)

Differential Revision: https://reviews.llvm.org/D23916

llvm-svn: 280404