X86-64: Split long/double constant array/field set

A long constant needs to be in a register to store to memory.
By allowing stores of constants that are outside of the range of
int32_t, we reduce register usage.

Also support sets of float/double constants by using integer stores.

Rename RegisterOrInt32LongConstant to RegisterOrInt32Constant as it
now handles any type of constant.

Change-Id: I025d9ef889a5a433e45aa03b376bae40f14197d2
Signed-off-by: Mark Mendell <mark.p.mendell@intel.com>