[FLINK-37735][serializer] Replace class.newInstance with constructor.newInstance

[X-czh]

What is the purpose of the change

Lower PojoSerializer newInstance cost for higher deserialization performance.

Brief change log

Replace class.newInstance with constructor.newInstance for PojoSerializer and TupleSerializer.

The performance gets boosted by ~5% on the Flink POJO benchmark (tested on my laptop with JDK17.0.14), and the boost is more significant on simpler structs. More detailed performance analysis could be found at FLINK-37735.
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Verifying this change

This change is already covered by existing POJO serializer tests.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[flinkbot]

CI report:

• eeea810 Azure: SUCCESS

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[X-czh]

@flinkbot run azure

[X-czh]

@flinkbot run azure

[nikita-ivanov-cc]

approve

[X-czh]

@huwh @FangYongs Could you help take a look?

[huwh]

LGTM， thanks for your contribution.