_collect_emulator_extras ran three passes in one body: the undeclared
files a platform's cores need, a second copy of an archive under the
subdirectory some cores read, and the scan a filename-agnostic core
allows. The last two are named now, complexity 98 to 54.
The archive-prefix pass had no test, and extracting it surfaced why that
mattered: it read an index from the enclosing scope, so on its own it
would have raised. Three tests cover it, including the case it exists to
prevent - claiming a prefixed path for an archive the collection does
not hold.
Abdessamad Derraz
6aa5685fc7