clamper: Provide integration tests using qemu

Leverage qemu to spawn bullseye and bookworm kernels with a minimal configuration to test tcp-mss-clamper.

This initial version only loads the eBPF program and validates that's been loaded successfully using bpftool

Based on https://github.com/bradfitz/embiggen-disk/blob/master/integration_test.go

Bug: T353279