Pass -mrelax-relocations=yes to $(TEST_AS)

Pass -mrelax-relocations=yes to $(TEST_AS)

x86_64_mov_to_lea5.o and x86_64_mov_to_lea6.o must be assembled with
-mrelax-relocations=yes since when assembler is configured with
--disable-x86-relax-relocations, R_X86_64_GOTPCRELX relocation won't
be generated.  This linker optimization requires R_X86_64_GOTPCRELX
relocation.

This patch also removed the duplicated x86_64_overflow_pc32.o target.

	* testsuite/Makefile.am (x86_64_mov_to_lea5.o): Pass
	-mrelax-relocations=yes to $(TEST_AS).
	(x86_64_mov_to_lea6.o): Likewise.
	(x86_64_overflow_pc32.o): Remove duplicated target.
	* testsuite/Makefile.in: Regenerated.