Bad URL in stacktrace if urlRoot specified

### Expected behaviour

Correct URL is printed in stacktrace

### Actual behaviour

Bad URL is printed in stacktrace

### Environment Details

```JSON
// package.json
{
  "devDependencies": {
    "karma": "^1.7.1",
    "karma-chrome-launcher": "^2.2.0",
    "karma-jasmine": "^1.1.0",
    "jasmine-core": "^2.8.0"
  }
}
```

```JavaScript
//karma.conf.js
module.exports = function (config) {
  config.set({
    urlRoot: '/__karma__',
    frameworks: ['jasmine'],
    files: ['tests/**/*.js'],
    reporters: ['progress'],
    colors: true,
    logLevel: config.LOG_INFO,
    autoWatch: true,
    browsers: ['Chrome'],
    singleRun: false
  });
};
```

```JavaScript
// tests/sub/foo.js
describe('foo', function () {
    it('test', function () {
        fail();
    });
});
```

### Steps to reproduce the behaviour

1. Run tests with `./node_modules/karma/bin/karma start`
2. Output:
```
9 11 2017 19:49:40.487:WARN [config]: urlRoot normalized to "/__karma__/"
29 11 2017 19:49:40.540:WARN [karma]: No captured browser, open https://localhost:9876/__karma__/
29 11 2017 19:49:40.546:INFO [karma]: Karma v1.7.1 server started at https://0.0.0.0:9876/__karma__/
29 11 2017 19:49:40.546:INFO [launcher]: Launching browser Chrome with unlimited concurrency
29 11 2017 19:49:40.560:INFO [launcher]: Starting browser Chrome
29 11 2017 19:49:40.980:INFO [Chrome 62.0.3202 (Linux 0.0.0)]: Connected on socket 3ny3gbgd6AeYqWRDAAAA with id 79121705
Chrome 62.0.3202 (Linux 0.0.0) foo test FAILED
        Failed
            at UserContext.<anonymous> (https://localhost:9876/__karma__tests/sub/foo.js:3:9)
Chrome 62.0.3202 (Linux 0.0.0): Executed 1 of 1 (1 FAILED) ERROR (0.003 secs / 0.003 secs)
```

Unexpected output part:
```
  at UserContext.<anonymous> (https://localhost:9876/__karma__tests/sub/foo.js:3:9)
```

Expected:
```
  at UserContext.<anonymous> (tests/sub/foo.js:3:9)
```

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Bad URL in stacktrace if urlRoot specified #2897

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Bad URL in stacktrace if urlRoot specified #2897

Description

Expected behaviour

Actual behaviour

Environment Details

Steps to reproduce the behaviour

Metadata

Metadata

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Labels

Type

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Development

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