Only filter requested events in wxEventBlocker.

Contrary to the documentation, wxEventBlocker always behaved as if the
event type to block was wxEVT_ANY: while it returned false for events
not on the blacklist, it never actually called the existing event
handler as it was meant to.

Fix by calling wxEvtHandler::ProcessEvent() in this case.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@76973 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775