Include locals information in gdb via the preexisting dwarf output.
As discussed I have a top level DIE for 'HPHP::TypedValue' with the same name
which gdb takes care of while doing the opaque type resolution.
This change is mostly for FB internal organizational reasons.
Building is not effected beyond the fact that the target now
lands in hphp/hhvm/hhvm rather than src/hhvm/hhvm.
mwilliams