Fix bootstrap comparison failure

Fix bootstrap comparison failure

Previously, bootstrap comparison failed when promoting symbols to
global because:

1. Randomness was used for promotion.
2. Order matters when partial linking, and such order was also random.

This commit fixes those issues.

gcc/ChangeLog:
2020-08-07  Giuliano Belinasssi <giuliano.belinassi@usp.br>

	* cgraphunit.c (childno): New variable.
	(maybe_compile_in_parallel): Store current child number.
	* gcc.c (sort_asm_files): New function.
	* toplev.c (init_additional_asm_names_file): Output child number.
	* toplev.h (init_additional_asm_names_file): Update interface.
	* tree.c (get_file_function_name): Do not use randomness when
	promoting names.