elf: Properly set sh_offset for .tbss sections

elf: Properly set sh_offset for .tbss sections

Set sh_offset for .tbss sections to their nominal offset after aligning.
They are not loaded from disk so the value doesn't really matter, except
when the .tbss section is the first one in a PT_TLS segment.  In that
case, it sets the p_offset for the PT_TLS segment, which according to
the ELF gABI ought to satisfy p_offset % p_align == p_vaddr % p_align.

bfd/

	PR ld/32896
	* elf.c (assign_file_positions_for_load_sections): Properly set
	sh_offset for .tbss sections.

ld/

	PR ld/32896
	* testsuite/ld-elf/tbss4.d: New file.
	* testsuite/ld-elf/tbss4.s: Likewise.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>