test-ssh: stablize for platform-specific shell quoting

Windows and OpenVMS use double quotes instead of single.

tests/test-ssh-bundle1.t

@@ -457,7 +457,7 b' debug output'
 
   $ hg pull --debug ssh://user@dummy/remote
   pulling from ssh://user@dummy/remote
-  running dummyssh user@dummy 'hg -R remote serve --stdio'
+  running dummyssh user@dummy ('|")hg -R remote serve --stdio('|") (re)
   sending hello command
   sending between command
   remote: 286

tests/test-ssh.t

@@ -445,7 +445,7 b' debug output'
 
   $ hg pull --debug ssh://user@dummy/remote
   pulling from ssh://user@dummy/remote
-  running dummyssh user@dummy 'hg -R remote serve --stdio'
+  running dummyssh user@dummy ('|")hg -R remote serve --stdio('|") (re)
   sending hello command
   sending between command
   remote: 286