anchor.diff:      options.sdkSummary = sdkSummary;
       IncrementalCompiler compiler =
           new IncrementalKernelGenerator(options, main);
  +    Stopwatch stopwatch = new Stopwatch()..start();
       var program = await compiler.computeDelta();
  +    print("Normal compile took ${stopwatch.elapsedMilliseconds} ms");
       libCount2 = serializeProgram(program);
       if (program.libraries.length != 2) {
         throw "Expected 2 libraries, got ${program.libraries.length}";
  
positive.code:   return options;
  }
  
  Future<bool> normalCompile(Uri input, Uri output) async {
    CompilerOptions options = getOptions();
    IncrementalCompiler compiler = new IncrementalKernelGenerator(options, input);
    var y = await compiler.computeDelta();
    await writeProgramToFile(y, output);
  
negative.code:         new IncrementalKernelGenerator(options, b, bootstrap);
      compiler.invalidate(main);
      compiler.invalidate(b);
      Stopwatch stopwatch = new Stopwatch()..start();
      var program = await compiler.computeDelta();
      print("Bootstrapped compile took ${stopwatch.elapsedMilliseconds} ms");
      if (program.libraries.length != 1) {
        throw "Expected 1 library, got ${program.libraries.length}";
      }
  