Add C# integration test which uses MSBuild

Author: mbg

csharp/ql/integration-tests/all-platforms/msbuild/Program.cs

@@ -0,0 +1,11 @@
+namespace Test
+{
+    public class Program
+    {
+        public static int Main(string[] args)
+        {
+            Console.WriteLine("Hello world!");
+            return 0;
+        }
+    }
+}

csharp/ql/integration-tests/all-platforms/msbuild/test.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+</Project>

csharp/ql/integration-tests/all-platforms/msbuild/test.py

@@ -0,0 +1,4 @@
+from create_database_utils import *
+
+# force CodeQL to use MSBuild by setting `LGTM_INDEX_MSBUILD_TARGET`
+run_codeql_database_create([], test_db="default-db", db=None, lang="csharp", extra_env={ 'LGTM_INDEX_MSBUILD_TARGET': 'Build' })