dwarf reader: drop (now) unused code related symbol table reading

The introduction of the new symtab reader incorporated much of the
existing functionality. Now that the most code parts are migrated to the
new symtab reader, we can safely remove the old code paths.

Ignoring the symbol table is not a thing anymore. The new symtab reader
does read the symtab unconditionally for consistency reasons. Hence also
remove all functionality around conditional symtab reading.

	* include/abg-dwarf-reader.h (set_ignore_symbol_table): Remove.
	(get_ignore_symbol_table): Likewise.
	* src/abg-dwarf-reader.cc (add_symbol_to_map): Likewise.
	(read_context::options_type::ignore_symbol_table): Likewise.
	(read_context::options_type): Adjust.
	(read_context::fun_addr_sym_map_): Remove.
	(read_context::fun_entry_addr_sym_map_): Likewise.
	(read_context::fun_syms_): Likewise.
	(read_context::var_addr_sym_map_): Likewise.
	(read_context::var_syms_): Likewise.
	(read_context::undefined_fun_syms_): Likewise.
	(read_context::undefined_var_syms_): Likewise.
	(read_context::initialize): Adjust.
	(read_context::lookup_elf_symbol_from_index): Remove.
	(read_context::fun_entry_addr_sym_map_sptr): Likewise.
	(read_context::fun_entry_addr_sym_map): Likewise.
	(read_context::fun_syms_sptr): Likewise.
	(read_context::fun_syms): Likewise.
	(read_context::var_syms_sptr): Likewise.
	(read_context::var_syms): Likewise.
	(read_context::undefined_fun_syms_sptr): Likewise.
	(read_context::undefined_var_syms_sptr): Likewise.
	(read_context::load_symbol_maps_from_symtab_section): Likewise.
	(read_context::load_symbol_maps): Likewise.
	(read_context::maybe_load_symbol_maps): Likewise.
	(set_ignore_symbol_table): Likewise.
	(get_ignore_symbol_table): Likewise.
	(create_default_var_sym): Likewise.
	(build_var_decl): Adjust.
	(function_is_suppressed): Likewise.
	(variable_is_suppressed): Likewise.
	(build_function_decl): Likewise.
	(add_symbol_to_map): Remove.
	(read_corpus_from_elf): Adjust.
	(build_corpus_group_from_kernel_dist_under): Likewise.
	* tools/abidw.cc (main): Likewise.

Reviewed-by: Giuliano Procida <gprocida@google.com>
Signed-off-by: Matthias Maennich <maennich@google.com>

include/abg-dwarf-reader.h

@@ -195,12 +195,6 @@ set_drop_undefined_syms(read_context& ctxt,
 void
 set_do_log(read_context& ctxt, bool f);
 
-void
-set_ignore_symbol_table(read_context &ctxt, bool f);
-
-bool
-get_ignore_symbol_table(const read_context &ctxt);
-
 void
 set_environment(read_context& ctxt,
 		ir::environment*);