[yaml2obj/obj2yaml] - Add support for SHT_HASH sections.

SHT_HASH specification is:
http://www.sco.com/developers/gabi/latest/ch5.dynamic.html#hash

In short the format is the following: it has 2 uint32 fields
in its header: nbucket and nchain followed by (nbucket + nchain)
uint32 values.

This patch allows dumping and parsing such sections.

Differential revision: https://reviews.llvm.org/D68085

llvm-svn: 373315