##### SUMMARY
When using SSH against a Windows host with PowerShell v5 the stderr when pipelining is not being used contains a nested CLIXML message in the stderr. We should be able to handle this correctly and not fail.

Currently I can only explicitly disable pipelining for Windows as it should always be enabled but there is a report where this has happened in the wild so it's not unheard of https://github.com/ansible/awx/issues/6990.

##### ISSUE TYPE
- Bug Report

##### COMPONENT NAME
ssh
powershell

##### ANSIBLE VERSION
```paste below
devel
```

##### CONFIGURATION
Not sure yet, need to figure out how pipelining was disabled on the Windows case.

##### OS / ENVIRONMENT
Targeting Windows Server with PowerShell v5 and the SSH default shell is `powershell.exe`


##### STEPS TO REPRODUCE
Not sure yet, can only replicate by connecting to SSH on a WIndows host and manually changing https://github.com/ansible/ansible/blob/devel/lib/ansible/plugins/connection/ssh.py#L464 to False.

##### EXPECTED RESULTS
Works just fine


##### ACTUAL RESULTS
Fails because the stderr looks like (see nested CLIXML header)
```paste below
b'#< CLIXML\r\n#< CLIXML\r\n<Objs Version="1.1.0.1" xmlns="http://schemas.microsoft.com/powershell/2004/04"><Obj S="progress" RefId="0"><TN RefId="0"><T>System.Management.Automation.PSCustomObject</T><T>System.Object</T></TN><MS><I64 N="SourceId">1</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj></Objs><Objs Version="1.1.0.1" xmlns="http://schemas.microsoft.com/powershell/2004/04"><Obj S="progress" RefId="0"><TN RefId="0"><T>System.Management.Automation.PSCustomObject</T><T>System.Object</T></TN><MS><I64 N="SourceId">1</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj><Obj S="progress" RefId="1"><TNRef RefId="0" /><MS><I64 N="SourceId">2</I64><PR N="Record"><AV>Preparing modules for first use.</AV><AI>0</AI><Nil /><PI>-1</PI><PC>-1</PC><T>Completed</T><SR>-1</SR><SD> </SD></PR></MS></Obj></Objs>')
```

user_home_path = self._unquote(user_home_path)
        if user_home_path == '~':
            script = 'Write-Output (Get-Location).Path'
        elif user_home_path.startswith('~\\'):
            script = 'Write-Output ((Get-Location).Path + "%s")' % self._escape(user_home_path[1:])
        else:
            script = 'Write-Output "%s"' % self._escape(user_home_path)
        return self._encode_script(script)
    def exists(self, path):
        path = self._escape(self._unquote(path))
        script = '''
            If (Test-Path "%s")
            {
                $res = 0;
            }
            Else
            {
                $res = 1;
            }
            Write-Output "$res";
            Exit $res;
         ''' % path
        return self._encode_script(script)
    def checksum(self, path, *args, **kwargs):