MIPS: Add the lo register to the clobber list in the madd-8.c and msub-8.c testcases.

MIPS: Add the lo register to the clobber list in the madd-8.c and msub-8.c testcases.

The lo register is not listed in the clobber list in the inline asm statement
for the madd-8.c and msub-8.c testcases.  This means that when building for the
n64 ABI GCC is free to use the lo register instead of the stack when
saving/restoring the clobbered registers.  Then then means that it decides to
use the msub/madd instruction to perform the "x - y * z" operation rather than
using mul; addu/subu which the test is looking for.

testsuite/
	* gcc.target/mips/madd-8.c: Add lo register to clobber list.
	* gcc.target/mips/msub-8.c: Ditto.

From-SVN: r227299