[FIXED HUDSON-7657] While testing from command prompt requires escaping of ^&<>|

with a ^ character, this is apparently not needed when cmd.exe /C is invoked from
Hudson.. commented that part of toWindowsCommand() and updated javadoc/unit test.


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@36903 71c3de6d-444a-0410-be80-ed276b4c234a