Restore previous behavior of "absolute_path()"

The function `absolute_path` that was provided by "pathtools" was redefined and now gives a "Path" object back as return value.

However, this leads to assertion errors when executing the test suite on FreeBSD, because there are now discrepancies between "PosixPath('/some/dir')" and "'/some/dir'".

Thus restore the original return value of "absolute_path" as is was done by "pathtools".  See also:

https://pythonhosted.org/pathtools/_modules/pathtools/path.html#absolute_path

src/watchdog/observers/kqueue.py

@@ -76,8 +76,6 @@
 import os.path
 import select
 
-from pathlib import Path
-
 from watchdog.observers.api import (
     BaseObserver,
     EventEmitter,
@@ -127,7 +125,7 @@
 
 
 def absolute_path(path):
-    return Path(path).resolve()
+    return os.path.abspath(os.path.normpath(path))
 
 # Flag tests.