Improve X86 handling of constants to Field/Array Set

AnTuTu 5.6 f.v.b() function on X86 showed several places where FP
constants were created using the stack, one in an inner loop.

Change ArraySet and *FieldSet to allow constants, and then generate
integer constant moves, rather than forcing the constant to be
materialized into a register. This will also help with register
pressure.

Change-Id: Ibebe2fed748a1bbeca47c36e9536b9b2357fc3cb
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>