Disable tests on non-Windows due to bugs related to .NET Core 2.1

https://github.com/dotnet/corefx/issues/23496
https://github.com/dotnet/cli/issues/7501

test/ArgumentForwardingTests/ArgumentForwardingTests.cs

@@ -42,7 +42,8 @@ namespace Microsoft.DotNet.Tests.ArgumentForwarding
         /// This is a critical scenario for the driver.
         /// </summary>
         /// <param name="testUserArgument"></param>
-        [Theory]
+        //  This test is "Windows only" for now due to https://github.com/dotnet/corefx/issues/23496
+        [WindowsOnlyTheory]
         [InlineData(@"""abc"" d e")]
         [InlineData(@"""ábc"" d é")]
         [InlineData(@"""abc""      d e")]

test/ArgumentForwardingTests/ArgumentForwardingTests.csproj

@@ -21,9 +21,10 @@
     <PackageReference Include="Microsoft.DotNet.PlatformAbstractions" Version="$(PlatformAbstractionsVersion)"/>
   </ItemGroup>
 
+  <!-- Disabled on non-Windows due to https://github.com/dotnet/corefx/issues/23496 -->
   <Target Name="PrecompileScript" 
           BeforeTargets="Build" 
-          Condition=" '$(IsCrossTargetingBuild)' != 'true' ">
+          Condition=" '$(IsCrossTargetingBuild)' != 'true' And '$(OS)' == 'Windows_NT'">
     <Exec Command="$(DotnetInOutputDirectory) publish ../ArgumentsReflector/ArgumentsReflector.csproj --output $(MSBuildThisFileDirectory)/$(OutputPath)" />
   </Target>
 

test/dotnet-store.Tests/GivenDotnetStoresAndPublishesProjects.cs

@@ -108,7 +108,8 @@ namespace Microsoft.DotNet.Cli.Publish.Tests
                     "    path: 'lib/netstandard1.3/NuGet.Configuration.dll'");
         }
 
-        [Fact]
+        //  Windows only for now due to https://github.com/dotnet/cli/issues/7501
+        [WindowsOnlyFact]
         public void ItPublishesAnAppWithMultipleProfiles()
         {
             var testAppName = "MultiDependentProject";