The `EnhancedStackTrace.ShowInStackTrace` probably should cache its results

[onyxmaster]

Hello.

I would like to propose that EnhancedStackTrace.ShowInStackTrace should cache its execution results, because since Type.GetCustomAttributesData throws NotImplementedException, the ShowInStackTrace method can quickly become a performance bottleneck when used often (at least if netstandard20 and net471 code are mixed in the same domain).