siso: match intermediate symlink dir with dir

Siso may not record intermediate symlink dir, but just as dir
if dir itself it not used as input
e.g.
   input: usr/include/libpng/png.h

   on disk
          usr/include/libpng -> linpng16
          usr/include/libpng16/png.h

In this case, two phase action's input root will have
usr/include/libpng/png.h, but when matching input root,
libpng was dir, but symlink on disk.

To match these intermediate symlink dir, if symlink points
to directory, consider it matches with dir.

Bug: b/527756492
Change-Id: Ia54445c98d9d43702f6ecc3e243134ab5324381f
Reviewed-on: https://chromium-review.googlesource.com/c/build/+/8130177
Reviewed-by: Yuke Liao <liaoyuke@google.com>
Auto-Submit: Fumitoshi Ukai <ukai@google.com>
Commit-Queue: Fumitoshi Ukai <ukai@google.com>