Instead of setting watches on individual files when a non-empty filespec is
given, always watch all the files but just ignore the events from the ones not
matching the filespec. This makes the code simpler and fixes several bugs.
See #14544.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72681 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775