On the second click on "Show desktop" button, the minimized windows
are not restored, because after the first click, and the addition to
`CSimpleArray<MINWNDPOS> g_MinimizedAll`, a call to `RestoreMinimizedNonTaskWnds()`
via `HSHELL_WINDOWACTIVATED` message clears the list of minimized windows.
Don't empty `g_MinimizedAll` while processing HSHELL_WINDOWCREATED or
HSHELL_WINDOWACTIVATED messages (bDestroyed=FALSE).
Empty `g_MinimizedAll` only when SendPulseToTray is called with bDestroyed=TRUE.
Addendum to e6bced7a35 and 70d7009ad9. CORE-19703 CORE-15369