Bug 1059942 - Make dump_syms to parse public symbols; r=ted

Currently, dump_syms does not look at public symbols if the object file
has debug info. This may cause it to skip some symbols that do not have
.debug_info section. Notably we see this at bionic routines implemented
in assembly. Details can be found at [1].

We apply patch [2] to enable dump_syms read public symbols even when
DWARF debug info is found.

[1] http://tinyurl.com/k3pxw5l

[2] https://breakpad.appspot.com/9684002/