LLDB top of tree SVN fails to attach to a MacOSX native process by pid only (no executable).

The problem was that the static DynamicLoaderDarwinKernel::Initialize() was recently changed to come before DynamicLoaderMacOSXDYLD::Initialize() which caused the DynamicLoaderDarwinKernel::CreateInstance(...) to be called before DynamicLoaderMacOSXDYLD::CreateInstance(...) and DynamicLoaderDarwinKernel would claim it could be the dynamic loader for a user space MacOSX process. The fix is to make DynamicLoaderDarwinKernel::CreateInstance() a bit more thourough when vetting the process so that it doesn't claim MacOSX user space processes.

<rdar://problem/25425373> 

llvm-svn: 264794