This implements various SIMD instructions related to
load, store, and lane manipulations for all engines.
Notablely, now our engines pass the following specification tests:
* simd_address.wast
* simd_const.wast
* simd_align.wast
* simd_laod16_lane.wast
* simd_laod32_lane.wast
* simd_laod64_lane.wast
* simd_laod8_lane.wast
* simd_lane.wast
* simd_load_extend.wast
* simd_load_splat.wast
* simd_load_zero.wast
* simd_store.wast
* simd_store16_lane.wast
* simd_store32_lane.wast
* simd_store64_lane.wast
* simd_store8_lane.wast
part of #484
Signed-off-by: Takeshi Yoneda <takeshi@tetrate.io>
Co-authored-by: Adrian Cole <adrian@tetrate.io>
