[mlir][LLVM] Handle access groups during inlining

Handling access groups is luckily rather trivial: Any access groups from the call instruction are simply appended to any memory operations.
This is similar to one of the steps when handling alias scopes.
This patch nevertheless implements it as a separate function purely for readability purposes as it uses a different interface than alias scopes.

Differential Revision: https://reviews.llvm.org/D155795