mips: additional test case for fix in VEX r2648

Test program that triggers different corner cases related to position of
branch instruction and max size of a translation block (60 instructions).
Fix for these issues has been submitted in r2648.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13248 a5019735-40e9-0310-863c-91ae7b9d1cf9