Align eh_frame FDEs according to their encoding

Align eh_frame FDEs according to their encoding

bfd/
	* elf-bfd.h (struct eh_cie_fde): Add u.cie.per_encoding_aligned8.
	* elf-eh-frame.c (size_of_output_cie_fde): Don't align here.
	(next_cie_fde_offset): New function.
	(_bfd_elf_parse_eh_frame): Set u.cie.per_encoding_aligned8.
	(_bfd_elf_discard_section_eh_frame): Align zero terminator to
	four bytes.  Align CIEs to four or eight bytes depending on
	per_encoding_aligned8.  Align FDEs according to their encoding.
	Pad last FDE to output section alignment.
	(_bfd_elf_write_section_eh_frame): Adjust to suit.  Remove
	assertion.
	* elf64-ppc.c (glink_eh_frame_cie): Delete padding.
	(ppc64_elf_size_stubs): Pad glink eh_frame as per elf-eh-frame.c.
	(ppc64_elf_finish_dynamic_sections): Adjust to suit.
ld/
	* testsuite/ld-elf/eh3.d: Adjust for eh_frame alignment change.
	* testsuite/ld-elf/eh6.d: Likewise.
	* testsuite/ld-alpha/tlsbin.dd: Likewise.
	* testsuite/ld-alpha/tlsbin.td: Likewise.
	* testsuite/ld-alpha/tlsbinr.dd: Likewise.
	* testsuite/ld-alpha/tlspic.dd: Likewise.
	* testsuite/ld-alpha/tlspic.rd: Likewise.
	* testsuite/ld-alpha/tlspic.sd: Likewise.
	* testsuite/ld-alpha/tlspic.td: Likewise.
	* testsuite/ld-mips-elf/eh-frame1-n64.d: Likewise.
	* testsuite/ld-mips-elf/eh-frame2-n64.d: Likewise.
	* testsuite/ld-mips-elf/eh-frame3.d: Likewise.
	* testsuite/ld-x86-64/pr20830a.d: Likewise.
	* testsuite/ld-x86-64/pr21038a.d: Likewise.
	* testsuite/ld-x86-64/pr21038b.d: Likewise.
	* testsuite/ld-x86-64/pr21038c.d: Likewise.