[Dependency-injection] CustomNormalizer not injected until set with priority

[metfan]

Symfony version(s) affected: 4.4.5

Description
After upgrade from 4.4.4 to 4.4.5, I see my app crashed because of missing CustomNormalizer.
I must add priority on the tag to see this normalizer injected in Serializer.

How to reproduce
With this simple config in service.yaml CustomeNormalizer is injected to Serializer before 4.4.5

Symfony\Component\Serializer\Normalizer\CustomNormalizer:

with 4.4.5 I must write:

Symfony\Component\Serializer\Normalizer\CustomNormalizer:
    tags:
        - { name: serializer.normalizer, priority: 100 }

[metfan]

probably related to #35916

[xabbuh]

@metfan Can you confirm that #35957 also fixes this issue?

[metfan]

@xabbuh yes #35957 fix this issue, I just checked.