SDL sometimes doesn't send BC.OnAppUnregistered in case HMI close an app with RESOURCE_CONSTRAINT reason

[dboltovskyi]

Bug Report

SDL sometimes doesn't send BC.OnAppUnregistered in case HMI close an app with RESOURCE_CONSTRAINT reason.

Occurrences

~0.5%

Reproduction Steps

1. SDL and HMI are started
2. App is registered on default mobile connection
3. App is activated
4. HMI sends BC.OnExitApplication with reason: RESOURCE_CONSTRAINT related to App to SDL

Expected Behavior

SDL sends BC.OnAppUnregistered notification to HMI

Observed Behavior

SDL doesn't send notification to HMI

OS & Version Information

• OS/Version: Ubuntu 18.04
• SDL Core Version: https://github.com/smartdevicelink/sdl_core/tree/release/7.0.0 (80973f4)
• Testing Against: ATF

Test Case, Sample Code, and / or Example App

• ATF Script: 025_OnExitApplication_RESOURCE_CONSTRAINT_one_app - needs to me run 1000 times
• Report and Logs: 2020-10-29_22-43-00_3561.tar.gz

[AKalinich-Luxoft]

@theresalech please notice this is not a regression issue related to wrong behavior of TCP transport with a pretty low occurrence.
PR with fix is linked and ready for Livio review

[theresalech]

@AKalinich-Luxoft, thank you for letting us know! If Luxoft would like to make this issue a priority for the next Core release (planned for April 2021), please make sure it is raised to the SDLC Steering Committee as such.

[ShobhitAd]

Closed via #3566