Avoid using GlobalTaskQueueFactory for TaskQueueForTest

To remove global task factory, rtc::TaskQueue need to loose it's convenient constructor
TaskQueueForTest can be used instead in tests and keep the convenient constructor.

Also cleanup the TaskQueueForTest a bit:
move the class to webrtc namespace
add default constructor
disallow copy using language construct instead of macro
cleanup build dependencies
rename build target (to match move out of the rtc namespace)

Bug: webrtc:10284
Change-Id: I17fddf3f8d4f363df7d495c28a5b0a28abda1ba7
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/127571
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27193}
diff --git a/video/BUILD.gn b/video/BUILD.gn
index 27697fd..a9a3c04 100644
--- a/video/BUILD.gn
+++ b/video/BUILD.gn
@@ -561,7 +561,7 @@
       "../rtc_base:rtc_base_tests_utils",
       "../rtc_base:rtc_numerics",
       "../rtc_base:rtc_task_queue",
-      "../rtc_base:rtc_task_queue_for_test",
+      "../rtc_base:task_queue_for_test",
       "../rtc_base/experiments:alr_experiment",
       "../rtc_base/task_utils:to_queued_task",
       "../system_wrappers",