Add some more comments explaining the purpose of some Register classes.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@222774 91177308-0d34-0410-b5e6-96231b3b80d8
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.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@222775 91177308-0d34-0410-b5e6-96231b3b80d8
When a process stops, set the StopInfo object on Windows.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@222776 91177308-0d34-0410-b5e6-96231b3b80d8