Implement PCMPxSTRx cases 0x0E, 0x34, 0x14, and reformat some of the
associated switch statements.  Fixes #326469, #327639, #328878
respectively.



git-svn-id: svn://svn.valgrind.org/vex@2864 8f6e269a-dfd6-0310-a8e1-e2731360e62c