Reenable template tests on Windows

Author: javiercn

src/ProjectTemplates/test/ProjectTemplates.Tests.csproj

@@ -7,8 +7,7 @@
     <TargetFramework>netcoreapp3.0</TargetFramework>
     <DefineConstants>$(DefineConstants);XPLAT</DefineConstants>
 
-    <!-- Workaround until https://github.com/aspnet/AspNetCore/issues/4321 is resolved. -->
-    <RunTemplateTests Condition="'$(OS)' != 'Windows_NT'">true</RunTemplateTests>
+    <RunTemplateTests>true</RunTemplateTests>
     <SkipTests Condition="'$(RunTemplateTests)' != 'true'">true</SkipTests>
     <!-- https://github.com/aspnet/AspNetCore/issues/6857 -->
     <BuildHelixPayload>false</BuildHelixPayload>