The `TEST-UNEXPECTED-FAIL | checks that docIds are unique and increasing | in chrome | Expected 9 to be less than 0` unit test failed in a recent test run in https://github.com/mozilla/pdf.js/pull/13837#issuecomment-890511627, but also locally once for me. Perhaps this goes wrong because the test depends on state that might be mutated if the tests are shuffled?

/cc @Snuffleupagus since this unit test was added in https://github.com/mozilla/pdf.js/pull/13813/commits/b18620ac0f196c6fa5a9e54a53fa6b915e19e843
);
      const pdfDoc = await loadingTask.promise;
      const pdfPage = await pdfDoc.getPage(1);
      const tree = await pdfPage.getStructTree();
      expect(tree).toEqual({
        role: "Root",
        children: [
          {
            role: "Document",
            children: [
              {
                role: "H1",
                children: [
                  {
                    role: "NonStruct",
                    children: [{ type: "content", id: "page2R_mcid0" }],
                  },
                ],
              },
              {
                role: "P",
                children: [
                  {
                    role: "NonStruct",
                    children: [{ type: "content", id: "page2R_mcid1" }],
                  },
                ],
              },
              {
                role: "H2",