Lower unboxing of literal SIMD vectors.
Lower unboxing of literal SIMD vectors.

Previously constant vectors on the left hand side of an operation would
need to be unboxed by loading the vector object, then loading the
actual vector. Now the vector data is stored in the function's literal
pool and can be loaded directly. Saves an instruction & memory load.

froggey/Mezzano,froggey/Mezzano