Get the field name from its parent when it doesn't have one when collecting fields (bug 1864136)

Some fields, somewhere under the Fields entry in Acroform, could have no name (in T)
but with a parent which has a name but which isn't somewhere under Fields.
As a side-effect, this patch prevents infinite loops because of potential cycles
under Fields.

test/integration/test_utils.mjs

@@ -176,6 +176,28 @@ async function getFirstSerialized(page, filter = undefined) {
   return (await getSerialized(page, filter))[0];
 }
 
+function getAnnotationStorage(page) {
+  return page.evaluate(() =>
+    Object.fromEntries(
+      window.PDFViewerApplication.pdfDocument.annotationStorage.serializable.map?.entries() ||
+        []
+    )
+  );
+}
+
+function waitForEntryInStorage(page, key, value) {
+  return page.waitForFunction(
+    (k, v) => {
+      const { map } =
+        window.PDFViewerApplication.pdfDocument.annotationStorage.serializable;
+      return map && JSON.stringify(map.get(k)) === v;
+    },
+    {},
+    key,
+    JSON.stringify(value)
+  );
+}
+
 function getEditors(page, kind) {
   return page.evaluate(aKind => {
     const elements = document.querySelectorAll(`.${aKind}Editor`);
@@ -398,6 +420,7 @@ export {
   clearInput,
   closePages,
   dragAndDropAnnotation,
+  getAnnotationStorage,
   getComputedStyleSelector,
   getEditorDimensions,
   getEditors,
@@ -427,6 +450,7 @@ export {
   scrollIntoView,
   serializeBitmapDimensions,
   waitForAnnotationEditorLayer,
+  waitForEntryInStorage,
   waitForEvent,
   waitForSelectedEditor,
   waitForSerialized,