Fix Bug#34943

Fix Bug#34943

* lisp/files-x.el (cl-lib): Require when compiling.
(hack-connection-local-variables): Regard connection-local
variables as safe.  (Bug#34943)

* lisp/shell.el (shell): Use `with-connection-local-variables' for
the whole code block.  (Bug#34943)

* lisp/net/tramp-adb.el (tramp-connection-local-safe-shell-file-names):
Do not set values.

* lisp/net/tramp-integration.el
(tramp-connection-local-safe-shell-file-names): Remove.
(shell-file-name, shell-command-switch): Do not add safe-local-variable
property.

* lisp/net/tramp.el (tramp-handle-shell-command): Use proper
buffer name.

* test/lisp/net/tramp-tests.el (tramp-test34-explicit-shell-file-name):
Tag it :unstable.