Restore partial analysis of analysis options files

pkg/analyzer/lib/src/summary/package_bundle_reader.dart

 import 'dart:io' as io;
 import 'dart:math' show min;
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/resolver.dart' show TypeProvider;
@@ skipping 21 matching lines @@
 
   ConflictingSummaryException(Iterable<String> summaryPaths, this.duplicatedUri,
       this.summary1Uri, this.summary2Uri) {
     // Paths are often quite long.  Find and extract out a common prefix to
     // build a more readable error message.
     var prefix = _commonPrefix(summaryPaths.toList());
     _message = '''
 These summaries conflict because they overlap:
 - ${summary1Uri.substring(prefix)}
 - ${summary2Uri.substring(prefix)}
-Both contain the file: ${duplicatedUri}.
+Both contain the file: $duplicatedUri.
 This typically indicates an invalid build rule where two or more targets
 include the same source.
   ''';
   }
 
   String toString() => _message;
 
   /// Given a set of file paths, find a common prefix.
   int _commonPrefix(List<String> strings) {
     if (strings.isEmpty) return 0;
@@ skipping 472 matching lines @@
       var file = resourceProvider.getFile(path);
       buffer = file.readAsBytesSync();
     } else {
       io.File file = new io.File(path);
       buffer = file.readAsBytesSync();
     }
     PackageBundle bundle = new PackageBundle.fromBuffer(buffer);
     addBundle(path, bundle);
   }
 }