Tell GitLab CI to continue running tests in .NET 8

fixes afc181c40
sort of defeats the purpose, but hey it was working before, and
compilation errors will still be caught automatically

.gitlab-ci.yml

@@ -201,8 +201,7 @@ run_tests:
   - job: build_asms_release
     artifacts: false
   script:
-  - Dist/BuildDebug.sh # populate output
-  - Dist/BuildTestRelease.sh -v normal
+  - Dist/BuildTestRelease.sh -v normal -p:TestProjTargetFrameworkOverride=net8.0
   stage: test
 
 .disabled_job_sast:

src/TestProjects.props

@@ -5,6 +5,9 @@
 		<OutputPath>$(ProjectDir)../../test_output</OutputPath>
 		<OutputType>Exe</OutputType>
 	</PropertyGroup>
+	<PropertyGroup Condition=" '$(TestProjTargetFrameworkOverride)' != '' AND '$(TargetFramework)' == 'net48' ">
+		<TargetFramework>$(TestProjTargetFrameworkOverride)</TargetFramework>
+	</PropertyGroup>
 	<ItemGroup>
 		<PackageReference Include="MSTest" PrivateAssets="all" />
 		<PackageReference Include="JunitXml.TestLogger" PrivateAssets="all" />