anchor.diff:              'dart2js',
               'dart2analyzer',
               'app_jit',
  -            'dart2app',  // TODO(rmacnak): Remove after updating bots.
  -            'dart2appjit',  // TODO(rmacnak): Remove after updating bots.
               'dartk',
               'dartkp'
             ],
  
positive.code:    * into a list of configurations with exactly one value per key.
     */
    List<Map> _expandConfigurations(Map configuration) {
      // TODO(rmacnak): Remove after updating bots.
      if (configuration['runtime'] == 'dart_app') {
        configuration['runtime'] = 'vm';
      }
      if (configuration['compiler'] == 'dart2app' ||
          configuration['compiler'] == 'dart2appjit') {
        configuration['compiler'] = 'app_jit';
      }
  
      // Expand the pseudo-values such as 'all'.
      if (configuration['arch'] == 'all') {
        configuration['arch'] = 'ia32,x64,simarm,simarm64,simmips,simdbc64';
  
negative.code:           [
              'vm',
              'dart_precompiled',
              'd8',
              'jsshell',
              'drt',
  