Add a couple more constant folding rules for vectors.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2844 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Implement TBL and TBX instructions.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2845 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Implement
LD2/ST2 (multiple structures, post index) (some cases)
LD1/ST1 (multiple structures, no offset)  (some cases)



git-svn-id: svn://svn.valgrind.org/vex/trunk@2846 8f6e269a-dfd6-0310-a8e1-e2731360e62c