Make sense also drop it everywhere. Anyway you cannot run tests for NS. You must use platform TFM

@Romfos It's too aggressive to drop it from TestFramework IMO. You can have a test utilities library that target netstandard2.0 that you then reference in your test projects. For adapter, the story is different, because adapter isn't intended to be used in test utility libraries and is only intended to be used in actual test projects that shouldn't target netstandard2.0.

We are not correctly testing .NET Framework of adapter in some cases, e.g, FileOperationTests. We wrap the whole class in #if !NET462, so we test only with .NET Framework 4.8. However, we use the netstandard2.0 assembly of the adapter in this case.

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 65.82%. Comparing base (f7f69d6) to head (c3724ea).
Report is 12 commits behind head on dev/v4.

@@            Coverage Diff             @@
##           dev/v4    #5882      +/-   ##
==========================================
+ Coverage   63.09%   65.82%   +2.73%     
==========================================
  Files         574      574              
  Lines       31434    31453      +19     
==========================================
+ Hits        19833    20705     +872     
+ Misses      11601    10748     -853