[FrameworkBundle] Added a missing test for TimedPhpEngine.
[FrameworkBundle] Fixed Stopwatch namespace.
merged branch jakzal/timed-php-engine-stopwatch-fix (PR #7703)

This PR was merged into the master branch.

Discussion
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[FrameworkBundle] Fixed a Stopwatch namespace

Also, added a test.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes (they're actually failing on PHP 5.3 but not because of this PR)
| Fixed tickets | none
| License       | MIT
| Doc PR        | none

Commits
-------

043a915 [FrameworkBundle] Fixed Stopwatch namespace.
2170dcb [FrameworkBundle] Added a missing test for TimedPhpEngine.