[keshavdandeva]

b/582676539

Prepares the Arrow reader for the job stream (b/581544197).

• Producer skips Read API responses without rows, fails fast when a response reports rows but has no record batch, and forwards a schema sent in the stream.
• Result set skips zero-row batches and builds its decoder from the first schema it sees.
• isBeforeFirst()/isLast() return false for an empty result.

[gemini-code-assist]

Code Review

This pull request refactors the BigQuery JDBC driver's Arrow result set processing to support streams with an unknown total row count, skip empty batches, and dynamically forward schemas. It also optimizes memory usage during Arrow batch deserialization by reading directly from the ByteString input stream instead of copying it to a heap byte array. Feedback is provided to wrap the newly introduced InputStream and ReadableByteChannel in a try-with-resources block to prevent potential static analysis warnings regarding unclosed resources.