Change `NVVM_SyncWarpOp` base class from `NVVM_Op` to `NVVM_IntrOp<"bar.warp.sync">`, which auto-generates `llvmEnumName = nvvm_bar_warp_sync` and registers it with `-gen-intr-from-llvmir-conversions` and `-gen-convertible-llvmir-intrinsics`. This enables LLVM IR to MLIR import. The hand-written `llvmBuilder` is removed as the default `LLVM_IntrOpBase` builder is equivalent.
Multi-Level Intermediate Representation
See https://mlir.llvm.org/ for more information.