Ensure options incompatible with micromips imply -mno-micromips

gcc/testsuite/

	* gcc.target/mips/mips.exp (mips-dg-options): -mips3d requires
	-mno-micromips.  MIPS32R1 and below require -mno-micromips.
	-march=loongson* and -march=octeon* require -mno-micromips.

From-SVN: r219641