Implement FCVTAS W_S and FCVTAU W_S.  Fixes #340509.


git-svn-id: svn://svn.valgrind.org/vex@2984 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Implement PRFM (immediate).  Fixes #335713.


git-svn-id: svn://svn.valgrind.org/vex@2985 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Handle all DSB/DMB/ISB variants.  Fixes #340033.


git-svn-id: svn://svn.valgrind.org/vex@2986 8f6e269a-dfd6-0310-a8e1-e2731360e62c