Revert changes in previous deltas that introduced new failures into

Revert changes in previous deltas that introduced new failures into
the linker testsuite.

	* aoutx.h (slurp_symbol_table): Revert previous delta.
	(slurp_reloc_table): Likewise.
	* compress.c (bfd_get_full_section_contents): Remove file size
	test.
	* coffgen.c (coff_get_normalized_symtab): Allow zero-sized symtabs
	and do not complain about linker generated files.