If a new platform is created/selected for an architecture, make it the selected platform so you can do things like:
% lldb ios-executable
(lldb) platform connect connect://localhost:11111

Prior to this fix, the host platform would be selected even though the target was using the ios-remote platform.

git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@217963 91177308-0d34-0410-b5e6-96231b3b80d8