Don't call the Process::SyncIOHandler in Target::Launch

Summary: This patch moves synchronization of iohandler to CommandObjectProcessLaunch::DoExecute like it was done in CommandObjectProcessContinue::DoExecute.

Reviewers: jingham, clayborg

Reviewed By: clayborg

Subscribers: lldb-commits, clayborg, jingham

Differential Revision: http://reviews.llvm.org/D9373

llvm-svn: 236699