Don't prefetch outside ModuleCacheRebuild thread.

[#56005352]

Msf::ModuleManager#add_path was prefetching the added
Metasploit::Model::Module::Path, but this meant that prefetching was
occuring outside the ModuleCacheRebuild thread.
Run specs in random order to detect dependencies

[#56005352]

Set the spec order to :random so that its easier to detect specs that
have unintential dependencies on the previously run spec or the sequence
or factory generated for the nth example.