Add temporary translation of Wasm's `load_splat` using Cranelift's `load` and `splat` instructions (#1347)
Add temporary translation of Wasm's `load_splat` using Cranelift's `load` and `splat` instructions (#1347)

If/when Cranelift gains a `load_splat` instruction, the `load + splat` could be replaced with a single Cranelift `load_splat`. This change allows the `simd_load_splat.wast` spec test to pass.
stoklund/cretonne,stoklund/cretonne,stoklund/cretonne