iselStmt, case Ist_Dirty: remove pointless conditional.  Spotted by
Coverity and Florian Krohm.


git-svn-id: svn://svn.valgrind.org/vex@2945 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Use const instead of a comment.


git-svn-id: svn://svn.valgrind.org/vex@2946 8f6e269a-dfd6-0310-a8e1-e2731360e62c