Add a testcase for i386 LD_AUDIT

This patch adds a testcase for i386 LD_AUDIT to check function return
and parameters passed in registers.

	* sysdeps/i386/Makefile (tests)[elf]: Add tst-audit3.
	(modules-names): Add tst-auditmod3a tst-auditmod3b.
	($(objpfx)tst-audit3): New rule.
	($(objpfx)tst-audit3.out): Likewise.
	* sysdeps/i386/tst-audit3.c: New file.
	* sysdeps/i386/tst-audit3.h: Likewise.
	* sysdeps/i386/tst-auditmod3a.c: Likewise.
	* sysdeps/i386/tst-auditmod3b.c: Likewise.