GH-115060: Speed up pathlib.Path.glob() by omitting initial stat() (#117831)

Since 6258844c, paths that might not exist can be fed into pathlib's
globbing implementation, which will call `os.scandir()` / `os.lstat()` only
when strictly necessary. This allows us to drop an initial `self.is_dir()`
call, which saves a `stat()`.

Co-authored-by: Shantanu <12621235+hauntsaninja@users.noreply.github.com>

Lib/pathlib/_abc.py

@@ -705,10 +705,8 @@ class PathBase(PurePathBase):
         anchor, parts = pattern._stack
         if anchor:
             raise NotImplementedError("Non-relative patterns are unsupported")
-        if not self.is_dir():
-            return iter([])
         select = self._glob_selector(parts, case_sensitive, recurse_symlinks)
-        return select(self, exists=True)
+        return select(self)
 
     def rglob(self, pattern, *, case_sensitive=None, recurse_symlinks=True):
         """Recursively yield all existing files (of any kind, including