fix: Make sure to select valid IAnalyzerResult from Buildalyzer (#2811)

Make sure to select valid IAnalyzerResult from Buildalyzer

Just like #1900 but for the InputFileResolver.

This was not an issue until phmonte/Buildalyzer#198 was reverted in phmonte/Buildalyzer@8e85a15 for the Buildalyzer 6.0.1 release. Before this change in Buildalyzer, the empty target framework was sorted last but since v6.0.1 it's sorted first instead.

Also, improve the NotSupportedException message when the language is undefined because `System.NotSupportedException: Specified method is not supported` is a terrible message.

src/Stryker.Core/Stryker.Core/Initialisation/InputFileResolver.cs

@@ -152,7 +152,7 @@ private List<IAnalyzerResult> AnalyzeSolution(StrykerOptions options)
                     var projectLogName = Path.GetRelativePath(options.WorkingDirectory, project.ProjectFile.Path);
                     _logger.LogDebug("Analyzing {projectFilePath}", projectLogName);
                     var buildResult = project.Build();
-                    var projectAnalyzerResult = buildResult.Results.FirstOrDefault();
+                    var projectAnalyzerResult = buildResult.Results.FirstOrDefault(a => a.TargetFramework is not null);
                     if (projectAnalyzerResult is not null)
                     {
                         projectsAnalyzerResults.Add(projectAnalyzerResult);
@@ -386,7 +386,7 @@ private ProjectComponentsBuilder GetProjectComponentBuilder(
                     _foldersToExclude,
                     _logger,
                     FileSystem),
-                _ => throw new NotSupportedException()
+                _ => throw new NotSupportedException($"Language not supported: {language}")
             };
     }
 }