* [RUNTIME] FastRPC interface for Hexagon runtime

Co-authored-by: Ravishankar Kolachana <quic_rkolacha@quicinc.com>
Co-authored-by: Krzysztof Parzyszek <kparzysz@quicinc.com>

* Explain store offset in a comment in launcher

Co-authored-by: Abhikrant Sharma <quic_abhikran@quicinc.com>
Co-authored-by: Ravishankar Kolachana <quic_rkolacha@quicinc.com>