Add amd64_x32_linux_record_tdep and amd64_x32_sys

Add amd64_x32_linux_record_tdep and amd64_x32_sys

X32 Linux system calls are diffferent from amd64 Linux system calls in
system call numbers as well as parameter types/values.  This patch adds
amd64_x32_linux_record_tdep and amd64_x32_syscall for x32.

	PR gdb/16304
	* amd64-linux-tdep.c (amd64_canonicalize_syscall): Handle x32
	system calls.
	(amd64_x32_linux_record_tdep): New.
	(amd64_linux_syscall_record_common): New function.
	(amd64_linux_syscall_record): Call
	amd64_linux_syscall_record_common with amd64_linux_record_tdep.
	(amd64_x32_linux_syscall_record): Call
	amd64_linux_syscall_record_common with
	amd64_x32_linux_record_tdep.
	(amd64_linux_init_abi_common): Move amd64_linux_record_tdep
	initialization and tdep->i386_syscall_record setup to ...
	(amd64_linux_init_abi): Here.
	(amd64_x32_linux_init_abi): Initialize
	amd64_x32_linux_record_tdep.  Set tdep->i386_syscall_record to
	amd64_x32_linux_syscall_record.
	* amd64-linux-tdep.h (amd64_x32_syscall): New enum.