Bug 1891742 - Try to fix intermittent comm/mail/test/browser/composition/browser_quoteMessage.js failure. r=freaktechnik

The logs show complaint about null gMsgCompose.
Also make some tests work with verify.

Differential Revision: https://phabricator.services.mozilla.com/D207772

--HG--
extra : amend_source : 1406206c7972d55f7bcdd37a88663ca0f1bb43f0

mail/components/compose/content/MsgComposeCommands.js

@@ -7450,7 +7450,7 @@ async function ComposeChangeLanguage(languages) {
   if (gSpellCheckingEnabled && checker?.spellCheckPending) {
     await new Promise(resolve => {
       Services.obs.addObserver(function observe(subject, topic) {
-        if (subject == gMsgCompose.editor) {
+        if (!gMsgCompose || subject == gMsgCompose.editor) {
           Services.obs.removeObserver(observe, topic);
           resolve();
         }

mail/test/browser/composition/browser_forwardUTF8.js

@@ -32,6 +32,7 @@ var folderToSendFrom;
 add_setup(async function () {
   requestLongerTimeout(2);
   folderToSendFrom = await create_folder("FolderWithUTF8");
+  registerCleanupFunction(() => folderToSendFrom.deleteSelf(null));
 });
 
 function check_content(window) {

mail/test/browser/composition/browser_quoteMessage.js

@@ -28,6 +28,7 @@ var folderToStoreMessages;
 
 add_setup(async function () {
   folderToStoreMessages = await create_folder("QuoteTestFolder");
+  registerCleanupFunction(() => folderToStoreMessages.deleteSelf(null));
 });
 
 add_task(async function test_quoteMessage() {

mail/test/browser/shared-modules/FolderDisplayHelpers.sys.mjs

@@ -715,9 +715,8 @@ export async function click_tree_row(aTree, aRowIndex) {
 async function _get_row_at_index(aViewIndex) {
   const win = get_about_3pane();
   const tree = win.document.getElementById("threadTree");
-  Assert.greater(
-    tree.view.rowCount,
-    aViewIndex,
+  await TestUtils.waitForCondition(
+    () => aViewIndex < tree.view.rowCount,
     `index ${aViewIndex} must exist to be clicked on`
   );
   tree.scrollToIndex(aViewIndex, true);