Move check for path.is_file to _py2, as it's only encountered there :(

Author: jaraco

importlib_resources/_py2.py

@@ -108,7 +108,10 @@ def path(package, resource):
     raised if the file was deleted prior to the context manager
     exiting).
     """
-    return trees.as_file(get(package, resource))
+    path = get(package, resource)
+    if not path.is_file():
+        raise FileNotFoundError(path)
+    return trees.as_file(path)
 
 
 def is_resource(package, name):

importlib_resources/trees.py

@@ -89,8 +89,6 @@ def as_file(path):
     Given a path-like object, return that object as a
     path on the local file system in a context manager.
     """
-    if not path.is_file():
-        raise FileNotFoundError(path)
     # todo: consider using functools.singledispatch
     wrapper = (
         _zip_path_as_file