It's valid to create a TypedArrayAttr or MixedContainerType with
nullptr, e.g.,
std::vector<mlir::Attribute> attrs = {mlir::StringAttr()};
builder.createArrayAttr(attrs);
The predicate didn't check if it's a nullptr and it ended up a crash in
the attribute static verifier. We always check if an attribute is null
so it's better to align the check for these two container type attr.
Reviewed By: rdzhabarov
Differential Revision: https://reviews.llvm.org/D121178
60d719b462