test: deflake watch tests
test: deflake watch tests

When a file is created, Watch implementations may send events about the
file's parent directory. Our tests weren't taking this into account, and
sometimes events about the directory would precede the file and cause
the tests to fail.

The fix in this change is to expect the events about the directory,
while still looking only for events related to the file.
I'm not sure that this is the correct fix.

Change-Id: Ief138a61191348c512c610ec1cdc877d245695ce
Reviewed-on: https://upspin-review.googlesource.com/9461
Reviewed-by: Rob Pike <4dc7c9ec434ed06502767136789763ec11d2c4b7@golang.org>

upspin/upspin,upspin/upspin