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.