MIPS32: Add MSA instruction set feature option

MSA (MIPS SIMD Architecture) is SIMD extension which will be used
for ART Vectorizer implementation.
Also extended instruction_set_features_mips_test.

Test: mma test-art-target in QEMU
Test: mma test-art-host-gtest

Change-Id: If77815cd75b7e86cd8b0eaa10f645c09053b8fd9