[llvm-readobj] Dump MachO Dysymtab command.

Example output:

File: <stdin>
Format: Mach-O 64-bit x86-64
Arch: x86_64
AddressSize: 64bit
Dysymtab {

ilocalsym: 0
nlocalsym: 6
iextdefsym: 6
nextdefsym: 2
iundefsym: 8
nundefsym: 0
tocoff: 0
ntoc: 0
modtaboff: 0
nmodtab: 0
extrefsymoff: 0
nextrefsyms: 0
indirectsymoff: 0
nindirectsyms: 0
extreloff: 0
nextrel: 0
locreloff: 0
nlocrel: 0

}

Differential Revision:	http://reviews.llvm.org/D12496

llvm-svn: 246474