[demangler] Fix node matchers

[urnathan]

Summary

This fixes up the matcher fallout from D120905

• Add instantiation tests to ItaniumDemangleTest, to make sure all match functions provide constructor arguments to the provided functor. This found some problems ...

• Fix the Node constructors that lost const qualification on arguments.

The node names are broken out into a def file by D122739, which this depends upon

[dblaikie]

llvm/include/llvm/Demangle/ItaniumDemangle.h

2377–2379

The modules-unfriendly nature of this worries me a bit.

Maybe we could change the FOR_EACH_NODE_KIND to a .def file instead? (basically take the macro out, put it in another (includable, intentionally non-modular) file that calls the includer-defined macro & undefs the macro at the end (so it doesn't persist/pollute other things))

We have a lot of these in LLVM, one example (though it handles a variet of different lists, which adds more complexity than will be needed here) is llvm/include/llvm/BinaryFormat/Dwarf.def

[dblaikie]

Sounds good

[urnathan]

committed d7692c0f9b06 2022-04-01 | [demangler] Fix node matcher test
to fix build bot: https://lab.llvm.org/buildbot/#/builders/216/builds/2249