<rdar://problem/11961650>

Update the debugserver "qProcessInfo" implementation to return the
cpu type, cpu subtype, OS and vendor information just like qHostInfo
does so lldb can create an ArchSpec based on the returned values.

Add a new GetProcessArchitecture to GDBRemoteCommunicationClient akin
to GetHostArchitecture.  If the qProcessInfo packet is supported,
GetProcessArchitecture will return the cpu type / subtype of the 
process -- e.g. a 32-bit user process running on a 64-bit x86_64 Mac
system. 

Have ProcessGDBRemote set the Target's architecture based on the 
GetProcessArchitecture when we've completed an attach/launch/connect.

llvm-svn: 170491