This PR adds support for the DLTI dialect by attaching it to the module attributes and introduces a utility function to determine if the target is big-endian, which is required for https://github.com/llvm/llvm-project/pull/142041. Some tests were updated because we now use `mlir::translateDataLayout`, which "updates" the `DataLayout` where the alignment for `long` is 8 instead of the previously 4. This updated is consistent with Incubator.