Do not re-resolve previously resolved modules

[keyboardDrummer]

Dafny does not use the same signature to compile a module and to verify it. As a result, it really creates two copies of each module: a regular copy and a copy called _Compile that is used only in the compiler.

To create _Compile modules, Dafny clones the original module, then swaps out a different signature and re-resolves the resulting module.

Related data: #2358