Handle stack split for x32

Handle stack split for x32

X32 uses cmp %fs:NN,%esp, lea NN(%rsp),%r10d, lea NN(%rsp),%r11d,
instead of cmp %fs:NN,%rsp, lea NN(%rsp),%r10, lea NN(%rsp),%r11.
This patch handles it.

	PR gold/17729
	* configure.ac (DEFAULT_TARGET_X86_64): Don't set for x32.
	(DEFAULT_TARGET_X32): Set for x32.
	* x86_64.cc (cmp_insn_32): New.
	(lea_r10_insn_32): Likewise.
	(lea_r11_insn_32): Likewise.
	(cmp_insn_64): Likewise.
	(lea_r10_insn_64): Likewise.
	(lea_r11_insn_64): Likewise.
	(Target_x86_64<size>::do_calls_non_split): Handle x32.
	* testsuite/Makefile.am (check_SCRIPTS): Add split_x32.sh.
	(check_DATA): Add split_x32 files.
	(split_x32_[1234n].o): New targets.
	(split_x32_[124]): New targets.
	(split_x32_[1234r].stdout): New targets.
	* testsuite/split_x32.sh: New file.
	* testsuite/split_x32_1.s: Likewise.
	* testsuite/split_x32_2.s: Likewise.
	* testsuite/split_x32_3.s: Likewise.
	* testsuite/split_x32_4.s: Likewise.
	* testsuite/split_x32_n.s: Likewise.
	* configure: Regenerated.
	* testsuite/Makefile.in: Likewise.