Preserved mscorlib for the non aot / aggressive trimming runs

Author: Steve Pfister

eng/testing/ILLink.Descriptor.xunit.xml

@@ -11,6 +11,7 @@
   </assembly>
   <assembly fullname="xunit.core"/>
   <assembly fullname="Microsoft.DotNet.XUnitExtensions"/>
+  <assembly fullname="mscorlib" />
   <assembly fullname="TestUtilities">
     <namespace fullname="System" />
   </assembly>

src/libraries/tests.proj

@@ -158,11 +158,6 @@
     <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Net.Http\tests\FunctionalTests\System.Net.Http.Functional.Tests.csproj" />
   </ItemGroup>
 
-  <ItemGroup Condition="'$(TargetOS)' == 'Browser' and '$(RunAOTCompilation)' == 'false' and '$(EnableAggressiveTrimming)' == 'true'">
-    <!-- mscorlib.dll not found -->
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Reflection.MetadataLoadContext/tests/System.Reflection.MetadataLoadContext.Tests.csproj" />
-  </ItemGroup>
-
   <ItemGroup>
     <ProjectReference Include="$(MSBuildThisFileDirectory)*\tests\**\*.Tests.csproj"
                       Exclude="@(ProjectExclusions)"