Handle dynamic as bottom inside of function type reps

test/codegen/expect/BenchmarkBase.js

 dart_library.library('BenchmarkBase', null, /* Imports */[
   "dart_runtime/dart",
   'dart/core'
 ], /* Lazy imports */[
 ], function(exports, dart, core) {
   'use strict';
   let dartx = dart.dartx;
   class Expect extends core.Object {
     static equals(expected, actual) {
       if (!dart.equals(expected, actual)) {
         throw `Values not equal: ${expected} vs ${actual}`;
       }
     }
     static listEquals(expected, actual) {
       if (expected[dartx.length] != actual[dartx.length]) {
         throw `Lists have different lengths: ${expected[dartx.length]} vs ${actual[dartx.length]}`;
       }
       for (let i = 0; dart.notNull(i) < dart.notNull(actual[dartx.length]); i = dart.notNull(i) + 1) {
         Expect.equals(expected[dartx.get](i), actual[dartx.get](i));
       }
     }
     fail(message) {
       throw message;
     }
   }
   dart.setSignature(Expect, {
-    methods: () => ({fail: [core.Object, [core.Object]]}),
+    methods: () => ({fail: [dart.dynamic, [dart.dynamic]]}),
     statics: () => ({
-      equals: [dart.void, [core.Object, core.Object]],
+      equals: [dart.void, [dart.dynamic, dart.dynamic]],
       listEquals: [dart.void, [core.List, core.List]]
     }),
     names: ['equals', 'listEquals']
   });
   class BenchmarkBase extends core.Object {
     BenchmarkBase(name) {
       this.name = name;
     }
     run() {}
     warmup() {
@@ skipping 46 matching lines @@
       measure: [core.double, []],
       report: [dart.void, []]
     }),
     statics: () => ({measureFor: [core.double, [core.Function, core.int]]}),
     names: ['measureFor']
   });
   // Exports:
   exports.Expect = Expect;
   exports.BenchmarkBase = BenchmarkBase;
 });