Implement LDRHT (Thumb), LDRSHT (Thumb), [LDR,ST]{S}[B,H]T (ARM).
Fixes 321891, 323035, 324047.  (vasily.golubev@gmail.com)



git-svn-id: svn://svn.valgrind.org/vex/trunk@2778 8f6e269a-dfd6-0310-a8e1-e2731360e62c