message: Provide default `affineMapComposition` and memory space on `MemRefType::get()` (NFC)
  This matches the builder API.
diff: @@ -366,8 +366,8 @@ public:
  /// well-formed MemRef type. Use getChecked to gracefully handle MemRefType
  /// construction failures.
  static MemRefType get(ArrayRef<int64_t> shape, Type elementType,
  - ArrayRef<AffineMap> affineMapComposition,
  - unsigned memorySpace) {
  + ArrayRef<AffineMap> affineMapComposition = {},
  + unsigned memorySpace = 0) {
  auto result = getImpl(shape, elementType, affineMapComposition, memorySpace,
  /*location=*/llvm::None);
  assert(result && "Failed to construct instance of MemRefType.");
  