The recent work to add SCons cache debugging (SERVER-39075) has revealed that we are actually pushing the separate debug info and the stripped binaries into the SCons cache. Normally, we tag all binaries and libraries as not being cacheable, but we had not realized that the later stages of the build pipeline were not similarly treated. These files are large and take up significant size in the cache, but will almost never be retrieved. We should tag them as non-cacheable, both to avoid the bandwidth cost of pushing them to the cache in the case where the cache is network shared, as well as to avoid the cache pressure effects of having such large and non-retrievable artifacts present in the cache.