Disable GetSTDOUT, GetSTDERR, and PutSTDIN on Windows.

These methods are difficult / impossible to implement in a way
that is semantically equivalent to the expectations set by LLDB
for using them.  In the future, we should find an alternative
strategy (for example, i/o redirection) for achieving similar
functionality, and hopefully deprecate these APIs someday.

llvm-svn: 222775