Try to fix Windows bots. Use absolute path instead of canonical.

pkg/analyzer_experimental/lib/src/generated/java_io.dart

 library java.io;
 
 import "dart:io";
 import 'package:path/path.dart' as pathos;
 
 class JavaSystemIO {
   static Map<String, String> _properties = new Map();
   static String getProperty(String name) {
     {
       String value = _properties[name];
@@ skipping 70 matching lines @@
     // "." or  "/" or  "C:\"
     if (result.length < 4) return null;
     return result;
   }
   JavaFile getParentFile() {
     var parent = getParent();
     if (parent == null) return null;
     return new JavaFile(parent);
   }
   String getAbsolutePath() => pathos.absolute(_path);
-  String getCanonicalPath() => _newFile().fullPathSync();
+  // TODO(scheglov) it seems that this method is broken on Windows
+//  String getCanonicalPath() => _newFile().fullPathSync();
+  String getCanonicalPath() => getAbsolutePath();
   JavaFile getAbsoluteFile() => new JavaFile(getAbsolutePath());
   JavaFile getCanonicalFile() => new JavaFile(getCanonicalPath());
   bool exists() {
     if (_newFile().existsSync()) {
       return true;
     }
     if (_newDirectory().existsSync()) {
       return true;
     }
     return false;
@@ skipping 12 matching lines @@
     List<JavaFile> files = [];
     List<FileSystemEntity> entities = _newDirectory().listSync();
     for (FileSystemEntity entity in entities) {
       files.add(new JavaFile(entity.path));
     }
     return files;
   }
   File _newFile() => new File(_path);
   Directory _newDirectory() => new Directory(_path);
 }