Implement VFPv4 VFMA and VFMS (F32 and F64 versions).  Fixes #331057.
Patch from Janne Hellsten (jjhellst@gmail.com) with algebraic
rearrangement for the VFMS cases so as to make result signs match with
the hardware when some of the inputs are infinities.



git-svn-id: svn://svn.valgrind.org/vex/trunk@2861 8f6e269a-dfd6-0310-a8e1-e2731360e62c