mips: flush the cache in perf/bigcode.c

MIPS needs to flush the cache after memcpy in perf/bigcode.c.
Otherwise, the executed code will likely be wrong.

This fixes issues with bigcode test on some MIPS platforms.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13550 a5019735-40e9-0310-863c-91ae7b9d1cf9