Remove PortablePdbReader

[pranavkm]

The type was meant to bridge some gaps in .NET Framework, but shouldn't be needed now that it's exclusively used in .NET Core. There is some code in the "package" that cleans up the stack trace which is the only thing we should need from it.

[analogrelay]

The existing code is working though right? It's just unnecessary?

[pranavkm]

This came up as part of discussing the new single file bundle format that's planned in 5.0. Things like Assembly.Location are going to be broken with it -

aspnetcore/src/Shared/StackTrace/StackFrame/PortablePdbReader.cs

Line 27 in 3c09d64

var metadataReader = GetMetadataReader(method.Module.Assembly.Location);

. If we were to try and react to it, we might very well remove this type since it's unnecessary.

[Marusyk]

Please assign it to me