[FL-3062] Fix unit tests (#2180)

* SubGHZ unit test: fail if async_tx is not started
* Memgr unit test: fix for multithreaded enviroment
* Unit tests: fix failed_tests count
* Unit tests: remove debug code
* Double update test: increase flipper detection time

Co-authored-by: あく <alleteam@gmail.com>

scripts/testing/await_flipper.py

@@ -24,7 +24,7 @@ def flp_serial_by_name(flp_name):
             return ""
 
 
-UPDATE_TIMEOUT = 60
+UPDATE_TIMEOUT = 60 * 4  # 4 minutes
 
 
 def main():