Crossgen /createpdb option doesn't have enough test coverage

[MichalStrehovsky]

I would expect we would at least try to use createpdb with Pri0 tests and make sure it's not bogus.

The option didn't work when default interface methods are present.

[mangod9]

@trylek -- Assume this is still relevant for crossgen2.

[trylek]

The test coverage is still poor; perhaps we could put something together as part of the 6.0.0 quality week of 8/23 (if I remember the date correctly). An interesting question is what exactly we need to proclaim that the PDB "is not bogus" in the sense of issue description. We'd either need to run some debugger tests or use the PDB manually to translate ETW information or some such; perhaps @hoyosjs might have some ideas or suggestions what could be the sweet spot on the balance between complexity of the testing process and the level of PDB validation.

[MichalStrehovsky]

An interesting question is what exactly we need to proclaim that the PDB "is not bogus"

The original bug I ran into when I filed this issue was that we would straight up crash while generating the PDB. Looks like the bug @trylek ran into in #70407 would be detectable by checking whether the PDB was generated at all?

If so, maybe the min bar would be just to: ask crossgen to generate a PDB + check some PDB is on disk after crossgen is done.