[CodeGen][NewPM] Consolidate PASS_NAME and CONSTRUCTOR in MachinePassRegistry.def (#80779)

This matches the optimization pipeline's PassRegistry.def.

I ran into a bug where CONSTRUCTOR wasn't always being used (in
PassBuilder::registerMachineFunctionAnalyses()).

Make DUMMY_* just accept a pass name, there's no point in having proper
constructors if the generated dummy class has a templated constructor
accepting arbitrary arguments.

Remove unused getPassNameFromLegacyName() as it was using this but for
no purpose.

Remove DUMMY_MACHINE_FUNCTION_ANALYSIS, we can just add those as we port
them.

This for some reason exposed missing mock calls in existing unittests.