Support more than 63 handles in QWindowsFileSystemWatcher

We spawn/stop additional threads as needed to watch any number of
files/directories. The old logic of using just one handle per watched
directory (regardless of how many files we watch in it.) is preserved.
In the worst case a thread is started per 63 files to watch.

This enabled Qt Creator to watch all .pro and .pri files even while
having qt's projects.pro and qtcreator.pro open.

Task-number: 185259, 253014
Reviewed-by: denis

0 files changed, 0 insertions, 0 deletions