Merge the dart:uri library into dart:core and update the Uri class

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

 library java.core;
 
 import "dart:math" as math;
-import "dart:uri";
 import "dart:collection" show ListBase;
 
 class JavaSystem {
   static int currentTimeMillis() {
     return (new DateTime.now()).millisecondsSinceEpoch;
   }
 
   static void arraycopy(List src, int srcPos, List dest, int destPos, int length) {
     for (int i = 0; i < length; i++) {
       dest[destPos + i] = src[srcPos + i];
@@ skipping 464 matching lines @@
       }
     } else if (sb.length > newLength) {
       var s = sb.toString().substring(0, newLength);
       sb = new StringBuffer(s);
     }
   }
   void clear() {
     sb = new StringBuffer();
   }
 }