[Spike Yaml] HOTFIX: Add libyaml-cpp to preload list of RTL simulators.

Created by: zchamski

This PR fixes spurious CI failures during tandem job executions. The root cause was an implicit path used to access the yaml-cpp shared library: instead of accessing the local copy of libyaml-cpp.so, the RTL simulators were accessing acopy of the lib located in the build space of Spike, and that space was eventually reclaimed for other CI jobs.