emu-concrete-method-dfns doesn't properly merge definitions from biblio with in-file definitions

[nicolo-ribaudo]

I'm updating ecmarkup in the import-defer proposal, which re-defines methods cor cyclic module records, and this is what I'm getting:

• LoadRequestedModules has an in-proposal definition in Cyclic Module Record, so it does not link to the "upstream" ones (there is one on Synthetic Module Record that it should link to)
• GetExportedNames has no definitions within the proposal, so auto-linking there properly points to ECMA-262.