FLINK-36479 remove deprecated method Table getSchema as

[jbalchan]

What is the purpose of the change

[FLINK-36479] (https://issues.apache.org/jira/browse/FLINK-36479)
Component: Table SQL / API

Remove deprecated methods Table getSchema and as

Brief change log

Remove deprecated methods Table getSchema and as

Verifying this change

This change is already covered by existing tests

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

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

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

[flinkbot]

CI report:

• 18df92e Azure: FAILURE

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[davidradl]

I see a test that uses this function in Scala in OverWindowValidationTest is has .
Over.partitionBy($"c").orderBy($"rowtime").preceding(2).following($"xx").as($"w"))

[xuyangzhong]

Hi, @jbalchan can you take a look at the ci failure?

[jbalchan]

@flinkbot run azure

[jbalchan]

@flinkbot run azure

[xuyangzhong]

Hi, @jbalchan any update? If you're busy, I'll take charge of this task and add you as co-author since the code freeze date for flink 2.0.0 is approaching...

[jbalchan]

Hi @xuyangzhong, I'm struggling to fix the scala test cases for this. I'm stuck on it and might need more time.
Since code freeze is approaching, please take over this.
I'm sooo sorry I couldn't figure out how to fix it...

[xuyangzhong]

No worries, I'll continue handling it :)