mips32/mips64: implement sdl, sdr, swl and swr without reading memory

New implementation of SDL, SDW, SWL and SWR instructions in a way in which
no memory read is required. This came as an issue for programs that map
memory as write-exec only.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2723 8f6e269a-dfd6-0310-a8e1-e2731360e62c
s390x: Make the CC_DEP1 field appear completely initialised when
writing a 32-bit floating point value into it.
Patch by Maran Pakkirisamy (maranp@linux.vnet.ibm.com).
Part of fixing BZ 307113.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2724 8f6e269a-dfd6-0310-a8e1-e2731360e62c