BuildKite: Install runsc under a unique runtime name.
BuildKite: Install runsc under a unique runtime name.

Without this, the runtime entry can get overwritten between
runs of different pipelines, potentially with different flags.

PiperOrigin-RevId: 453589305

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor