Search through all memory regions of the core file for

both a user process dyld and for a kernel binary -- we
will decide which to prefer after one or both have been
located.

It would be faster to stop the search thorugh the core
segments one we've found a dyld/kernel binary - but that
may trick us into missing the one we would prefer.

<rdar://problem/19806413> 

llvm-svn: 228910