gprofng: Refactor readSymSec for using BFD's asymbol struct

gprofng: Refactor readSymSec for using BFD's asymbol struct

This patch refactors a number of gprofng internal functions for using
more BFD data types and functions.
Stabs::readSymSec is a function which reads the symbols of an ELF file
mapping them into an internal structure. To use BFD asymbols, the
Elf::elf_getsym is changed from custom reading of the symbols from
.symtab and .dynsym section to BFD enable functions. A new function is
introduced which returns the number of either static or dynamic symbols,
named Elf::elf_getSymCount. Both Elf functions are used by
Stabs::readSymSec refactoring.

Also, this patch removes reading symbols, SUNW_ldnsym section as it is
only used by now defunct Studio compiler. However, it adds the reading
of both static and dynamic symbols, previously, only either one was
processed.

Signed-off-by: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>