This adds simple serialization and deserialization of the signature
provided when a {WebAssembly.Function} object is constructed. For now
this signature is only used by the {WebAssembly.Function.type} method,
but will soon be used when importing such functions as well.

R=jkummerow@chromium.org
TEST=mjsunit/wasm/type-reflection
BUG=v8:7742

Change-Id: If4a687ea537d8c12f4f01a7d3ac5a795ceb999c6
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1632211Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61898}