… (patrickcarlohickman)

This PR was squashed before being merged into the 3.4 branch (closes #28497).

Discussion
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[VarDumper] Fix global dump function return value for PHP7

Retarget of PR #28491. Reposting description below, with relevant updates.

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

In 3.4, the global `dump()` helper function in the VarDumper component was updated to return the arguments passed in to it. However, due to reusing the argument variable in the function, this introduces a bug in PHP7 in the return value of the function.

The variable used in the `foreach` loop overwrites the value passed in by the first argument. In PHP5, this is okay. In PHP7, even though the argument is passed by value, the value returned by `func_get_args()` is affected by changes to the arguments inside the function. This is a change from PHP5.

From the documentation for [`func_get_args()`](http://php.net/manual/en/function.func-get-args.php):

> If the arguments are passed by reference, any changes to the arguments will be reflected in the values returned by this function. As of PHP 7 the current values will also be returned if the arguments are passed by value.

This PR simply changes the name of the variable used in the `foreach` loop. It also adds a test file to test the return value of the global `dump()` function.

This is my first contribution to Symfony, so please let me know if the issue should be resolved in a different manner, or if the test should be modified in any way.

Thanks,
Patrick

Commits
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0def211 [VarDumper] Fix global dump function return value for PHP7