Attach (recommended) or Link to PDF file here:
[LesAccentsFrancais(1).pdf](https://github.com/mozilla/pdf.js/files/6369604/LesAccentsFrancais.1.pdf)

Steps to reproduce the problem:
1. Search for "a" and  click on "Highlight All"

What is the expected behavior? (add screenshot)
The two "A" in "FRANÇAIS" must be highlighted

What went wrong? (add screenshot)
They aren't but "R" and "N" are.
![image](https://user-images.githubusercontent.com/5641725/115959448-8f760880-a50c-11eb-9a88-dd14ae3bd6bc.png)

Reproductible in Firefox nightly or in a local dev environment.
/* Copyright 2020 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
"use strict";
const Jasmine = require("jasmine");
async function runTests(results) {
  const jasmine = new Jasmine();
  jasmine.jasmine.DEFAULT_TIMEOUT_INTERVAL = 30000;
  jasmine.loadConfig({
    random: false,
    spec_dir: "integration",
    spec_files: [
      "scripting_spec.js",
      "annotation_spec.js",
      "accessibility_spec.js",
    ],
  });
  jasmine.addReporter({
    jasmineDone(suiteInfo) {},