Support wasm select instruction with V128-typed operands on AArch64.

* this requires upgrading to wasmparser 0.67.0.

* There are no CLIF side changes because the CLIF `select` instruction is
  polymorphic enough.

* on aarch64, there is unfortunately no conditional-move (csel) instruction on
  vectors.  This patch adds a synthetic instruction `VecCSel` which *does*
  behave like that.  At emit time, this is emitted as an if-then-else diamond
  (4 insns).

* aarch64 implementation is otherwise straightforwards.

crates/lightbeam/Cargo.toml

@@ -24,7 +24,7 @@ more-asserts = "0.2.1"
 smallvec = "1.0.0"
 thiserror = "1.0.9"
 typemap = "0.3"
-wasmparser = "0.66.0"
+wasmparser = "0.67.0"
 
 [dev-dependencies]
 lazy_static = "1.2"

crates/lightbeam/wasmtime/Cargo.toml

@@ -13,6 +13,6 @@ edition = "2018"
 
 [dependencies]
 lightbeam = { path = "..", version = "0.21.0" }
-wasmparser = "0.66"
+wasmparser = "0.67"
 cranelift-codegen = { path = "../../../cranelift/codegen", version = "0.68.0" }
 wasmtime-environ = { path = "../../environ", version = "0.21.0" }