Implement Sign-extension operators

[bbyalcinkaya]

Sign-extension operators proposal introduces new numeric instructions for sign-extending 8/16/32 bit integers. It has been standardized and implemented in major platforms. Rustc supports these instructions as of version 1.70.0-nightly.

New opcodes and instructions:

instr ::= ...
        | 0xC0                  =>  i32.extend8_s
        | 0xC1                  =>  i32.extend16_s
        | 0xC2                  =>  i64.extend8_s
        | 0xC3                  =>  i64.extend16_s
        | 0xC4                  =>  i64.extend32_s

Besides implementing the syntax and semantics in K, it requires switching to a more up-to-date Python Wasm binary parser library that supports these instructions. ethereum / py-wasm hasn't received any updates since 2019.

[bbyalcinkaya]

#523