CL/aarch64: implement the wasm SIMD i32x4.dot_i16x8_s instruction

This patch implements, for aarch64, the following wasm SIMD extensions

  i32x4.dot_i16x8_s instruction
  https://github.com/WebAssembly/simd/pull/127

It also updates dependencies as follows, in order that the new instruction can
be parsed, decoded, etc:

  wat          to  1.0.27
  wast         to  26.0.1
  wasmparser   to  0.65.0
  wasmprinter  to  0.2.12

The changes are straightforward:

* new CLIF instruction `widening_pairwise_dot_product_s`

* translation from wasm into `widening_pairwise_dot_product_s`

* new AArch64 instructions `smull`, `smull2` (part of the `VecRRR` group)

* translation from `widening_pairwise_dot_product_s` to `smull ; smull2 ; addv`

There is no testcase in this commit, because that is a separate repo.  The
implementation has been tested, nevertheless.

cranelift/interpreter/src/step.rs

@@ -571,6 +571,7 @@ where
         Opcode::AtomicLoad => unimplemented!("AtomicLoad"),
         Opcode::AtomicStore => unimplemented!("AtomicStore"),
         Opcode::Fence => unimplemented!("Fence"),
+        Opcode::WideningPairwiseDotProductS => unimplemented!("WideningPairwiseDotProductS"),
 
         // TODO: these instructions should be removed once the new backend makes these obsolete
         // (see https://github.com/bytecodealliance/wasmtime/issues/1936); additionally, the