[jdt-core-dev] Remember to keep Scanner and PublicScanner in sync

[Philippe P Mulet <philippe_mulet@xxxxxxxxxx>]

Whenever Scanner is touched, its mirror PublicScanner should be refreshed
accordingly.
We are sometimes forgetting to do so, and this leads to potential
inconsistencies.

PublicScanner's class body should be exactly the same as the Scanner's
class body (simply rename constructors after paste is done)