The new dotnet SDK `ParallelCompilation=true` causing issues in TypeProviders

I'm linking this here, because the TypeProvider code is included with this repository as well.

ProvidedTypeDefinition member realization is not thread-safe, causes users to get errors like `FS0193: type 'X' is not compatible with type 'X'` and `FS0001: type 'X' does not match type 'X'` under `ParallelCompilation=true` (new default option).

Further details and suggested fix in the TypeProvider SDK repository:
https://github.com/fsprojects/FSharp.TypeProviders.SDK/issues/521

Start by reading the linked FSharp.TypeProviders.SDK issue 521, which contains the further details and suggested fix. Trace how ProvidedTypeDefinition member realization behaves with ParallelCompilation=true and verify that the reported FS0193 and FS0001 errors no longer occur.

Written by the indexing model from the issue text.