[wasm] Re-enable tests that were disabled due to the earlier emsdk bump

System.Linq.Tests.csproj: dotnet#64774

System.Text.Json.Tests.csproj: dotnet#64775

System.Text.RegularExpressions.Tests.csproj: dotnet#64769

System.Threading.Channels.Tests.csproj: dotnet#65012

System.Collections.Immutable.Tests.csproj: dotnet#65335

src/libraries/tests.proj

@@ -277,18 +277,6 @@
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetOS)' == 'Browser' and '$(RunDisabledWasmTests)' != 'true' and '$(RunAOTCompilation)' != 'true'">
-    <!-- https://github.com/dotnet/runtime/issues/64774 -->
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Linq\tests\System.Linq.Tests.csproj" />
-
-    <!-- https://github.com/dotnet/runtime/issues/64775 -->
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Text.Json\tests\System.Text.Json.Tests\System.Text.Json.Tests.csproj" />
-    <!-- https://github.com/dotnet/runtime/issues/64769 -->
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Text.RegularExpressions\tests\System.Text.RegularExpressions.Tests.csproj" />
-    <!-- https://github.com/dotnet/runtime/issues/65012 -->
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Threading.Channels\tests\System.Threading.Channels.Tests.csproj" />
-
-    <!-- https://github.com/dotnet/runtime/issues/65335 -->
-    <ProjectExclusions Include="$(MSBuildThisFileDirectory)System.Collections.Immutable\tests\System.Collections.Immutable.Tests.csproj" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(TargetOS)' == 'Browser' and '$(RunDisabledWasmTests)' != 'true'">