Fix modulo and bitwise operators.

test/codegen/expect/expect.js

 dart_library.library('expect', null, /* Imports */[
   'dart_sdk'
 ], function(exports, dart_sdk) {
   'use strict';
   const core = dart_sdk.core;
   const dart = dart_sdk.dart;
   const dartx = dart_sdk.dartx;
   const expect = Object.create(null);
   expect.Expect = class Expect extends core.Object {
     static _truncateString(string, start, end, length) {
       if (dart.notNull(end) - dart.notNull(start) > dart.notNull(length)) {
         end = dart.notNull(start) + dart.notNull(length);
       } else if (dart.notNull(end) - dart.notNull(start) < dart.notNull(length)) {
         let overflow = dart.notNull(length) - (dart.notNull(end) - dart.notNull(start));
         if (overflow > 10) overflow = 10;
         start = dart.notNull(start) - ((overflow + 1) / 2)[dartx.truncate]();
         end = dart.notNull(end) + (overflow / 2)[dartx.truncate]();
         if (dart.notNull(start) < 0) start = 0;
         if (dart.notNull(end) > dart.notNull(string[dartx.length])) end = string[dartx.length];
       }
       if (start == 0 && end == string[dartx.length]) return string;
       let buf = new core.StringBuffer();
       if (dart.notNull(start) > 0) buf.write("...");
       for (let i = start; dart.notNull(i) < dart.notNull(end); i = dart.notNull(i) + 1) {
         let code = string[dartx.codeUnitAt](i);
         if (dart.notNull(code) < 32) {
           buf.write("\\x");
           buf.write("0123456789abcdef"[dartx.get]((dart.notNull(code) / 16)[dartx.truncate]()));
-          buf.write("0123456789abcdef"[dartx.get](dart.notNull(code) % 16));
+          buf.write("0123456789abcdef"[dartx.get](code[dartx['%']](16)));
         } else {
           buf.writeCharCode(string[dartx.codeUnitAt](i));
         }
       }
       if (dart.notNull(end) < dart.notNull(string[dartx.length])) buf.write("...");
       return buf.toString();
     }
     static _stringDifference(expected, actual) {
       if (dart.notNull(expected[dartx.length]) < 20 && dart.notNull(actual[dartx.length]) < 20) return null;
       for (let i = 0; i < dart.notNull(expected[dartx.length]) && i < dart.notNull(actual[dartx.length]); i++) {
@@ skipping 254 matching lines @@
   expect.AssumeDynamic = class AssumeDynamic extends core.Object {
     AssumeDynamic() {
     }
   };
   dart.setSignature(expect.AssumeDynamic, {
     constructors: () => ({AssumeDynamic: [expect.AssumeDynamic, []]})
   });
   // Exports:
   exports.expect = expect;
 });