Add bool QObjectPrivate::moveToThread() which returns the success state
of the attempt to move the object to the new thread. For Qt7 the public
signature of QObject::moveToThread() should be changed to directly
return this value.
[ChangeLog][QtCore][QObject] QObject::moveToThread() now returns a
boolean success state.
Pick-to: 6.7
Change-Id: I8441c8155a76b804b473ab9c45c2be6840ef1677
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>