Fix (Bug#32218). Do not merge with master

Fix (Bug#32218).  Do not merge with master

* doc/misc/trampver.texi:
* lisp/net/trampver.el: Change version to "2.3.4.26.2".
(customize-package-emacs-version-alist): Add Tramp version
integrated in Emacs 26.2.

* lisp/net/tramp.el (tramp-handle-file-truename):
* lisp/net/tramp-adb.el (tramp-adb-handle-file-truename):
* lisp/net/tramp-sh.el (tramp-sh-handle-file-truename): Fix problem
with trailing slash.  (Bug#32218)

* test/lisp/net/tramp-tests.el (tramp-test21-file-links):
Remove `tramp--test-emacs27-p' check.