Skip switch symbol tests fail in "release mode"

[MarcoRossignoli]

closes #389
Temporary skip tests in release mode.

/cc @tonerdo @petli

[codecov]

Codecov Report

Merging #390 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #390   +/-   ##
=======================================
  Coverage   87.13%   87.13%           
=======================================
  Files          16       16           
  Lines        2106     2106           
=======================================
  Hits         1835     1835           
  Misses        271      271

[MarcoRossignoli]

@tonerdo I tried to fix checking right line in release but it doesn't work...the issue raise only on Windows/Release

[MarcoRossignoli]

I did some test with Ubuntu 18.04 and I get same exception from release config...maybe we should use a different Ubuntu image on appveyor to get consistent behaviour Ubuntu1804 https://www.appveyor.com/updates/
VS 2019 will be available this month appveyor/ci#2907 (comment)

[MarcoRossignoli]

Another idea could be avoid to rely on "machine wide sdks" and download run/build/test with "specific" sdk in a xplat way https://docs.microsoft.com/en-us/dotnet/core/tools/dotnet-install-script so we would have same "compiler", in my day-by-day work I'm used to do that.

[tonerdo]

What version of Ubuntu does AppVeyor use by default?

[MarcoRossignoli]

We use Ubuntu https://github.com/tonerdo/coverlet/blob/master/appveyor.yml#L4 and from AppVeyor docs

Linux images:
Ubuntu or Ubuntu1604 - Ubuntu 16.04
Ubuntu1804 - Ubuntu 18.04