Revert "Use the regular dotnet test command invocation"

This reverts commit 41bc33d.

.gitignore

@@ -201,4 +201,3 @@ FakesAssemblies/
 project.lock.json
 
 artifacts/
-/test/TestApp-*

Build.ps1

@@ -30,6 +30,9 @@ if($LASTEXITCODE -ne 0) { throw 'pack failed' }
 
 Write-Output "build: Testing"
 
-& dotnet test test\Serilog.Settings.Configuration.Tests\Serilog.Settings.Configuration.Tests.csproj
+# Dotnet test doesn't run separate TargetFrameworks in parallel: https://github.com/dotnet/sdk/issues/19147
+# Workaround: use `dotnet test` on dlls directly in order to pass the `--parallel` option to vstest.
+# The _reported_ runtime is wrong but the _actual_ used runtime is correct, see https://github.com/microsoft/vstest/issues/2037#issuecomment-720549173
+& dotnet test test\Serilog.Settings.Configuration.Tests\bin\Release\*\Serilog.Settings.Configuration.Tests.dll --parallel
 
-if($LASTEXITCODE -ne 0) { throw 'unit tests failed' }
+if($LASTEXITCODE -ne 0) { throw 'unit tests failed' }