Reenable System.Runtime.Serialization.Xml.Tests (#68921)

* Reenable `System.Runtime.Serialization.Xml.Tests`

This was disabled due to #59926,
which was then tracked by #61061
.

The stack overflow is due to one specific test though, and the rest of
the tests can be enabled if we skip this one - `DCS_DeeplyLinkedData`.

* Disable the test with `SkipOnPlatform` instead, for wasm, as it is

.. unlikely to be fixed (- vargaz).

Author: radical

src/libraries/System.Runtime.Serialization.Xml/tests/DataContractSerializer.cs

@@ -4256,6 +4256,7 @@ public static void DCS_TypeWithPrimitiveKnownTypes()
     }
 
     [ActiveIssue("https://github.com/dotnet/runtime/issues/1417", TestPlatforms.OSX)]
+    [SkipOnPlatform(TestPlatforms.Browser, "Causes a stack overflow")]
     [Fact]
     public static void DCS_DeeplyLinkedData()
     {

src/libraries/tests.proj

@@ -333,8 +333,6 @@
 
   <!-- Aggressive Trimming related failures -->
   <ItemGroup Condition="('$(TargetOS)' != 'Browser' and '$(RunAOTCompilation)' == 'true' and '$(MonoForceInterpreter)' != 'true') or ('$(TargetOS)' == 'Browser' and '$(BuildAOTTestsOnHelix)' == 'true' and '$(RunDisabledWasmTests)' != 'true')">
-    <!-- Issue: https://github.com/dotnet/runtime/issues/59926 -->
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Runtime.Serialization.Xml\tests\System.Runtime.Serialization.Xml.Tests.csproj" />
   </ItemGroup>
 
   <ItemGroup Condition="('$(TargetOS)' != 'Browser' and '$(RunAOTCompilation)' == 'true' and '$(MonoForceInterpreter)' != 'true') or ('$(TargetOS)' == 'Browser' and '$(BuildAOTTestsOnHelix)' == 'true' and '$(RunDisabledWasmTests)' != 'true') or ('$(TargetOS)' == 'iOS' and '$(BuildTestsOnHelix)' == 'true')">