[xharness] Add project configuration to run Jenkins-style tests. (#3249)

tests/xharness/xharness.csproj

@@ -34,6 +34,10 @@
     <StartAction>Project</StartAction>
     <StartArguments>--verbose --jenkins:server --autoconf --rootdir ..</StartArguments>
   </PropertyGroup>
+  <PropertyGroup Condition=" '$(RunConfiguration)' == 'Run Jenkins tests' ">
+    <StartAction>Project</StartAction>
+    <StartArguments>--verbose --jenkins --autoconf --rootdir ..</StartArguments>
+  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Xml" />