patch 9.1.0107: CI: Fix MacOS-14 tests

Problem:  CI: Fix MacOS-14 tests (after 9.1.0070)
Solution: Re-enable sound tests by granting Mic access,
          disable Test_diff_screen because of buggy MacOS diff
          (non GNU version), re-enable Test_term_gettitle()
          (Yee Cheng Chin)

macos-14 runner was turned on in #13943, but it had to turn off a few
tests in order for CI to run. Re-enable them and fix the underlying
issues.

* `Test_diff_screen`: The test failure is due to a bug in Apple's diff
  utility. Apple introduced a new diff tool based on FreeBSD in macOS 13
  and it has buggy behaviors when using unified diff (`-U0`) and the
  diff is on the first line of the file. Simply disable this test for
  now if we detect Apple diff (instead of the old GNU diff). Can
  re-enable this in the future if Apple fixes the issue.
* `Test_play_event` / `Test_play_silent`: GitHub Actions currently has
  an issue with playing sound in CI in macos-14 runners. It for some
  reason triggers a microphone permission dialog popup which blocks the
  CI action (see https://github.com/actions/runner-images/issues/9330).
  To fix this, add a temporary step in macos-14 to manually allow
  microphone permissions in the runner.
* `Test_term_gettitle`: I could not reproduce the failure, so I just
  turned it on and it seems to run just fine. Maybe it's a timing issue
  and whatnot but either way that should be fixed when we can reproduce
  the issue.

closes: #14032

Signed-off-by: Yee Cheng Chin <ychin.git@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/testdir/test_diffmode.vim

@@ -871,8 +871,8 @@ func VerifyInternal(buf, dumpfile, extra)
 endfunc
 
 func Test_diff_screen()
-  if has('osx') && !empty($CI) && system('uname -m') =~# 'arm64'
-    throw 'Skipped: FIXME: This test fails on M1 Mac on GitHub Actions'
+  if has('osxdarwin') && system('diff --version') =~ '^Apple diff'
+    throw 'Skipped: unified diff does not work properly on this macOS version'
   endif
 
   let g:test_is_flaky = 1