tests: fix forknotify.py on windows
tests: fix forknotify.py on windows

Windows interprets 'foo.txt' as a literal filename while "foo.txt" is treated
as expected.

(cherry picked from commit 5122ea7190f85952ef27153bb1778831efb3e0ec)

reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin