Fixed an issue in the DWARF parser that was causing forward declarations

to not get resolved.

Fixed the "void **isa_ptr" variable inside the objective C verifier to start
with a '$' character so we don't go looking for it in our program.

Moved the lookup for "$__lldb_class" into the part that knows we are looking
for internal types that start with a '$'.

llvm-svn: 118488