ProcessMachCore had (until 2013-01-29) some simple checks to find a kernel

ProcessMachCore had (until 2013-01-29) some simple checks to find a kernel
in a core file if it didn't start at the beginning of a memory segment.
I added more sophisticated kernel location code to DynamicLoaderDarwinKernel
and removed the simple one in ProcessMachCore.  Unfortunately the kernel
DynamicLoader doesn't get a chance to search around in memory unless there's
a hint that this might be a kernel debug session.  It was easy ot make the
kernel location code static in DynamicLoaderDarwinKernel and call it from
ProcessMachCore on the start of the session, so that's what I did.
<rdar://problem/13326647>

llvm-svn: 176405