Support compiling contracts with Rust v1.70+

[assafmo]

Starting from v1.70, Rust uses the Wasm sign extension opcodes when compiling to Wasm. Our Wasm parser for static analysis had to be updated in order to correctly parse these opcodes.

Refs:

• https://github.com/CosmWasm/cosmwasm/issues/1727
• https://github.com/CosmWasm/cosmwasm/pull/1743
• https://github.com/WebAssembly/sign-extension-ops/blob/master/proposals/sign-extension-ops/Overview.md