CPU stacks shows 100% broken stacks for universal traces

[noahfalk]

When opening a universal trace in PerfView and then looking at the CPU stacks view, PerfView warns there are 100% broken stacks:

Some of the stacks I looked do look like they might be missing some frames around the root of the stack or failing to resolve an entrypoint in libc.so.6, but I don't think 100% of them are broken.

[brianrob]

I think that our logic for detecting broken stacks is really only applicable to traces that originate from ETW. It would be good for us to not run this analysis on traces that don't originate from ETW. We may need to persist the origin of the data in the ETLX file if we don't already have this information, and then don't prompt the user with this error for non-ETW traces.