Symfony version(s) affected: 4.4.10

Description
When using the !iterator tag in yaml service definition files it does not support comments between the array initializer brackes. The bug occurs in constructor arguments as well when using the calls defintion.

How to reproduce
Create a services.yaml and paste the following contents:

    Foo\BarInterface:
        class: Foo\Bar
        arguments:
            - [!iterator [
                  '@service_a',
#                '@service_b',
            ]]

You will get an exception: Uncaught Symfony\Component\DependencyInjection\Exception\InvalidArgumentException: "!iterator" tag only accepts arrays of "@service" references in "yaml".