[HttpKernel] [WebProfilerBundle] added HTTP status to profiler search result

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | yes
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #12944
| License       | MIT
| Doc PR        |

With this PR HTTP status codes are provided in the search results to simplify identification of particular requests.
For the schema-less storage implementations (memcache(d), redis, mongodb) and the default file storage, it should work without purging existing profiles. But the code could be simplified, if it is an option to expect old profiles to be purged. For database driven storages (mysql, sqlite), the `sf_profiler_data` table must be dropped anyway (if the table isn't altered manually by adding the `status_code` column). Thus the changes are not fully BC.

![profiler-search-results](https://cloud.githubusercontent.com/assets/2466932/5499453/3cc6ad70-8730-11e4-81e5-13bfd1140d00.png)