Remove the old SIMD decoder entirely.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2873 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Implement FMUL 2d_2d_d[], 4s_4s_s[], 2s_2s_s[].


git-svn-id: svn://svn.valgrind.org/vex/trunk@2874 8f6e269a-dfd6-0310-a8e1-e2731360e62c