gold: Convert x86-64 GOTPCRELX only if addend == -4

gold: Convert x86-64 GOTPCRELX only if addend == -4

Convert x86-64 GOTPCRELX relocations only if addend == -4.

	PR gold/26939
	* x86_64.cc (Target_x86_64<size>::Scan::local): Check
	get_r_addend() == -4 for GOTPCRELX conversion.
	(Target_x86_64<size>::Scan::global): Likewise.
	(Target_x86_64<size>::Relocate::relocate): Likewise.
	* testsuite/Makefile.am (check_DATA): Add
	x86_64_mov_to_lea15.stdout and x86_64_mov_to_lea16.stdout.
	(MOSTLYCLEANFILES): Add x86_64_mov_to_lea15 and
	x86_64_mov_to_lea16.
	(x86_64_mov_to_lea9.o): New target.
	(x86_64_mov_to_lea10.o): Likewise.
	(x86_64_mov_to_lea15): Likewise.
	(x86_64_mov_to_lea16): Likewise.
	(x86_64_mov_to_lea15.stdout): Likewise.
	(x86_64_mov_to_lea16.stdout): Likewise.
	* testsuite/Makefile.in: Regenerated.
	* testsuite/x86_64_mov_to_lea.sh: Updated.
	* testsuite/x86_64_mov_to_lea5.s: New file.