Make thread stopping in ThreadBasedExecutor more safe

[IlyaMuravjov]

Description

Previously ThreadBasedExecutor:

• wasn't actually killing timed out threads (ThreadDeath was caught by kotlin.runCatching)
• wasn't waiting for old thread to die before starting a new one, causing race condition
• was able to forcefully stop() a thread even during clean up operations, causing java.lang.IllegalStateException: Cannot start new transaction without ending existing transaction

How to test

Manual tests

Generate integration tests for OrderService from spring-boot-testing project with low hanging test time out.

There should be no Caused by: java.lang.IllegalStateException: Cannot start new transaction without ending existing transaction.

Some time out tests should generate.

Self-check list

• I've set the proper labels for my PR (at least, for category and component).
• PR title and description are clear and intelligible.
• I've added enough comments to my code, particularly in hard-to-understand areas.
• The functionality I've repaired, changed or added is covered with automated tests.
• Manual tests have been provided optionally.
• The documentation for the functionality I've been working on is up-to-date.