Attach (recommended) or Link to PDF file here:
[occurmin0.pdf](https://github.com/mozilla/pdf.js/files/7340277/occurmin0.pdf)

Configuration:
- Web browser and its version: 95.0a1 (2021-10-13) (64-bit)
- Operating system and its version: Windows 10


Steps to reproduce the problem:
1. Open form in pdf.js

What is the expected behavior? (add screenshot)
Form is blank (subform `nomin`  does not display)
What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/7104454/137184675-d48027c0-1f17-4faa-bc97-b45814b38e36.png)

subform `nomin` displays, even though it's subform is set to `<occur max="-1" min="0" />`

if (!ref) {
        continue;
      }
      const nodes = searchNode(
        this.root,
        dataNode,
        ref,
        false ,
        false 
      );
      if (!nodes) {
        warn(`XFA - Invalid reference: ${ref}.`);
        continue;
      }
      for (const node of nodes) {
        if (!node[$isDescendent](this.datasets)) {
          warn(`XFA - Invalid ref (${ref}): must be a datasets child.`);
          continue;
        }
        const labelNodes = searchNode(
          this.root,
          node,
          labelRef,
          true ,
          false 
        );
        if (!labelNodes) {
          warn(`XFA - Invalid label: ${labelRef}.`);
          continue;
        }