Adjust compare_link_order for unstable qsort

Adjust compare_link_order for unstable qsort

In a cross toolchain for nios2-elf target and x86_64-w64-mingw32 host
using binutils 2.37, we observed a failure that didn't show up on
x86_64-linux-gnu host:  testcase pr25490-5.s was failing with

C:\path\to\nios2-elf-ld.exe: looping in map_segments
FAIL: __patchable_function_entries section 5

    	* ldelfgen.c (compare_link_order): Don't use section id in
	sorting.  Keep original ordering instead.  Update comments.