Check 64-bit relocation addend overflow for x32

bfd/

	* elf64-x86-64.c (elf_x86_64_relocate_section): Check addend
	overflow for R_X86_64_RELATIVE64.

gas/

	* config/tc-i386.c (tc_gen_reloc): Check x32 addend overflow
	for BFD_RELOC_64.

gas/testsuite/

	* gas/i386/ilp32/ilp32.exp: Run reloc64-inval.

	* gas/i386/ilp32/reloc64.s: Add tests for ".quad".
	* gas/i386/ilp32/reloc64.d: Updated.

	* gas/i386/ilp32/reloc64-inval.l: New file.
	* gas/i386/ilp32/reloc64-inval.s: Likewise.

ld/testsuite/

	* ld-x86-64/ilp32-11.d: New file.
	* ld-x86-64/ilp32-11.s: Likewise.

	* ld-x86-64/x86-64.exp: Run ilp32-11.