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.
