[DependencyInjection] Add exception for service name not dumpable in PHP

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #8485 #8030
| License       | MIT
| Doc PR        | n/a

Throws an exception when the DIC is dumped to PHP, before generating invalid PHP.
The regex comes from the PHP doc: http://www.php.net/manual/en/language.oop5.basic.php