mips64: add test cases for Cavium BBIT032 and BBIT132

This is a follow up to VEX r3028. This change adds two test cases
for Cavium instructions BBIT032 and BBIT132.

Issue tracked in BZ #339288.

Patch by Maran Pakkirisamy.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14792 a5019735-40e9-0310-863c-91ae7b9d1cf9