[0.4.14][NTUSER][SHELL32_APITEST] Fix regressions with taskbar panes CORE-17330 ...

[0.4.14][NTUSER][SHELL32_APITEST] Fix regressions with taskbar panes CORE-17330 (#3289) (#3294) & CORE-13584

fixes CORE-17330 'Regression, many installers that should have only 1 taskbar pane, now have 2 of them erroneously'
which was introduced by 0.4.14-dev-369-g 141cf04239f3049c1c180fb2c6c3aa84b13c8590
and made ros behave a lot different than previous and future releases would perform.
The main fix was picked from 0.4.15-dev-1126-g 58b0558f94abee52ce1c261063d4f4b884e96310 (#3294)
and the new ShellHook testcase from 0.4.15-dev-1123-g 0089291751837d977431c85b6d8d6b1232fbb67b (#3289)
The implementation atm passes all those 384 new ShellHookTests.

Beside that it entirely fixes the very old:
CORE-13584 'Winamp 5.666 erroneously has a secret tab shown in taskbar'

But brings back:
CORE-15669 'DVD Write Now 1.5.12 SP2 setup has no taskbar pane' (which was never working in any earlier release up to now)
but which we had fixed for a very short moment in master since the guilty 0.4.14-dev-369-g 141cf04239f3049c1c180fb2c6c3aa84b13c8590
That alone would be no biggy, but it also unhides?/introduces? for me the new:
CORE-17338 'Can not open a context menu in the taskbar pane of Double Commander setup, instantly closes'

Well in sum it is an improvement, but we are not in urgent need of porting it back any further than 0.4.14 yet,
because older releases would only benefit from CORE-13584 'Winamp...'