Fixed test cases failing when the Intl extension is not installed

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

I tested the 2.3 branch against PHP 5.5.12 with the following ICU versions:

* none
* 4.0
* 4.2
* 4.4
* 4.6
* 4.8
* 49
* 50
* 51
* 52
* 53

This PR contains the related fixes.