Fix for translation of \!= to \!identical(), but use == and \!= for Enum.

editor/util/plugins/com.google.dart.java2dart/resources/java_core.dart

 library java.core;
 
 import "dart:math" as math;
 
 final Stopwatch nanoTimeStopwatch = new Stopwatch();
 
 class JavaSystem {
   static int currentTimeMillis() {
     return (new DateTime.now()).millisecondsSinceEpoch;
   }
@@ skipping 368 matching lines @@
 }
 
 bool javaBooleanOr(bool a, bool b) {
   return a || b;
 }
 
 bool javaBooleanAnd(bool a, bool b) {
   return a && b;
 }
 
+int javaByte(Object o) {
+  return (o as int) & 0xFF;
+}
+
 class JavaStringBuilder {
   StringBuffer sb = new StringBuffer();
   String toString() => sb.toString();
   JavaStringBuilder append(x) {
     sb.write(x);
     return this;
   }
   JavaStringBuilder appendChar(int c) {
     sb.writeCharCode(c);
     return this;
@@ skipping 38 matching lines @@
     if (!_matches.moveNext()) {
       return false;
     }
     _match = _matches.current;
     return true;
   }
   String group(int i) => _match[i];
   int start() => _match.start;
   int end() => _match.end;
 }