[Serializer] fix denormalization of basic property-types in XML and CSV

[fabpot]

Q	A
Feature PR	symfony/symfony#33850
PR author(s)	@mkrauser
Merged in	5.2-dev

[carsonbot]

Thank you for this issue.
There has not been a lot of activity here for a while. Has this been resolved?

[carsonbot]

Hello? This issue is about to be closed if nobody replies.

[mkrauser]

@carsonbot I'll take a look at this, thanks for notifying me ;-)

[carsonbot]

Thank you for this issue.
There has not been a lot of activity here for a while. Has this been resolved?

[javiereguiluz]

Closing in favor of #17912, a meta-issue that groups all pending serializer-related issues so we can easily check them.