workingctx: correctly compute the flag for noexec filesystems+merge
This bug happens if the filesystem doesn't support exec-bit, during merges,
for example in 24ed7a541f23 on the hg repo.
If f is not in p1, but is in p2 and has the x-bit in p2, since the dirstate is
based on p1, and the FS doesn't support the exec-bit, the dirstate can't
"guess" the right bit.
We instead fix it in workingcontext.flags()/manifest.
#!/bin/sh
"$TESTDIR/hghave" inotify || exit 80
hg init
echo "[extensions]" >> $HGRCPATH
echo "inotify=" >> $HGRCPATH
echo % inserve
hg inserve -d --pid-file=hg.pid
cat hg.pid >> "$DAEMON_PIDS"
# let the daemon finish its stuff
sleep 1
echo % empty
hg debuginotify
mkdir a
sleep 1
echo % only 'a'
hg debuginotify
rmdir a
sleep 1
echo % empty again
hg debuginotify
kill `cat hg.pid`