[MLIR] Enable distribution target in standalone builds Invoke llvm_distribution_add_targets() when doing standalone build explicitly in order to create the `distribution` target. Differential Revision: https://reviews.llvm.org/D136269 GitOrigin-RevId: 14d9ef29304ee16802657311911813aec5bdb9cf
See https://mlir.llvm.org/ for more information.