[minor] Move on from java8 for three core modules

[dossett]

Move on from Java 8 in parquet-{common,column,hadoop}. This PR was created with codex and this is how it describes the changes:

What changed (Java 11 cleanups enabled by dropping Java 8):

• Replaced Arrays.asList(...) and other collection boilerplate with List.of(...) where nulls aren’t used, reducing allocations and improving clarity.
• Used Set.of(...) for small constant sets to simplify initialization.
• Tightened helper/collection usages in tests to lean on Java 9+ convenience factories.
• Kept Arrays.asList(...) where nulls are required to preserve behavior.

[dossett]

There's a CI failure that I really don't think is related to my change. Is this a known flaky test?

Error:  org.apache.parquet.column.values.bitpacking.TestByteBitPacking512VectorLE.unpackValuesUsingVector -- Time elapsed: 3.877 s <<< ERROR!
java.lang.OutOfMemoryError: Java heap space```

[Fokko]

Nice one @dossett

[Fokko]

Set.of is also immutable 👍