Fix Tramp's file-attributes cache

Fix Tramp's file-attributes cache

* lisp/net/tramp-adb.el (tramp-adb-handle-file-executable-p):
Check also for sticky bit.
(tramp-adb-handle-file-readable-p): Simplify.

* lisp/net/tramp-gvfs.el (tramp-gvfs-handle-file-executable-p):
Check also for sticky bit.  Force `file-attributes' check.

* lisp/net/tramp-sh.el (tramp-sh-handle-file-executable-p):
Check also for sticky bit.
(tramp-sh-handle-file-readable-p)
(tramp-sh-handle-file-writable-p): Simplify.

* lisp/net/tramp-sudoedit.el (tramp-sudoedit-handle-file-executable-p):
Check also for sticky bit.
(tramp-sudoedit-handle-file-readable-p)
(tramp-sudoedit-handle-file-writable-p): Simplify.

* lisp/net/tramp.el (tramp-use-file-attributes): Fix docstring.
(tramp-handle-file-readable-p, tramp-handle-file-writable-p):
Force `file-attributes' check.  Use `file-truename' for symbolic links.
(tramp-check-cached-permissions): New optional argument FORCE.
Fix symlink check.  Check also for sticky bit.  (Bug#77402)

* test/lisp/net/tramp-tests.el
(tramp-test20-file-modes-without-file-attributes)
(tramp-test21-file-links-without-file-attributes): New tests.