[mlir] Unranked memref type has no rank

[jpienaar]

Summary

UnrankedMemRefType doesn't have a rank but previously this was just
checking for unranked tensor. Avoids failure later if one queries the shape
post checking if ranked.

mlir/lib/IR/StandardTypes.cpp

int64_t ShapedType::getNumElements() const {
   int64_t num = 1;
   for (auto dim : shape)
     num *= dim;
   return num;
 }
 
 int64_t ShapedType::getRank() const { return getShape().size(); }
 
-bool ShapedType::hasRank() const { return !isa<UnrankedTensorType>(); }
+bool ShapedType::hasRank() const {
+  return !isa<UnrankedMemRefType>() && !isa<UnrankedTensorType>();
+}
 
 int64_t ShapedType::getDimSize(unsigned idx) const {
   assert(idx < getRank() && "invalid index for shaped type");
   return getShape()[idx];
 }
 
 bool ShapedType::isDynamicDim(unsigned idx) const {
   assert(idx < getRank() && "invalid index for shaped type");