Add sdiv and smod instruction support to bpf2c

[dthaler]

Description

Add support to bpf2c for the signed division and modulo instructions as specified in ietf-wg-bpf/ebpf-docs#42

Testing

Manually tested with latest bpf_conformance suite (in bpf_conformance main branch) using

bpf_conformance_runner --test_file_directory C:\Users\dthal\git\ebpf\bpf_conformance\build\tests --plugin_path C:\Users\dthal\git\ebpf\ebpf-for-windows\x64\Debug\bpf2c_plugin.exe --cpu_version v4 --exclude_regex "imm-" --plugin_options "--include C:\Users\dthal\git\ebpf\ebpf-for-windows\include"

Documentation

This PR includes a doc change to update the list of what instructions are supported.
It also lists bpf_conformance tests for the same, although the latest release of bpf_conformance still doesn't include them yet.
It also fixes a cut-and-paste error for opcode 0x06.

Installation

No impact