[AMORO-3853] Support Java 17 and removing reflective/internal dependencies in Flink modules

[xxubai]

Why are the changes needed?

The mixed Flink modules still had several Java 17 blockers, including hard-coded build/toolchain settings, runtime failures caused by JDK proxy and module encapsulation, and brittle reflection against Flink private internals.

This patch makes the mixed Flink Java 17 path buildable, testable, and packageable again.

Close #3853.

Brief change log

• Align Java 17 build settings across affected modules and remove hard-coded JDK/toolchain constraints.
• Reduce Flink-side dependence on private/internal reflection by switching to public APIs or explicit wrappers where possible.
• Upgrade dependencies more smoothly
• Prepare for upgrading Iceberg version and Iceberg V3 support

How was this patch tested?

• Add some test cases that check the changes thoroughly including negative and positive cases if possible
• Add screenshots for manual tests if appropriate
• Run test locally before making a pull request

Test commands:

• ./mvnw -nsu -pl amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common -am test -DfailIfNoTests=false
• ./mvnw -nsu -pl amoro-format-mixed/amoro-mixed-flink/amoro-mixed-flink-common,amoro-format-mixed/amoro-mixed-flink/v1.17/amoro-mixed-flink-1.17,amoro-format-mixed/amoro-mixed-flink/v1.18/amoro-mixed-flink-1.18 -am -DskipTests package

Documentation

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

[j1wonpark]

The reflection fallback block (lines 548-560) can be removed entirely.

SplitLocalOutput (the private inner class Flink returns from createOutputForSplit) is still registered in WatermarkOutputMultiplexer at the point releaseOutputForSplit is called — the split is not unregistered until internal.releaseOutputForSplit(splitId) returns. So calling watermarkOutput.emitPeriodicWatermark() at the reader level already covers this split: it iterates all currently-registered split outputs and computes the combined minimum watermark.

Suggested simplification:

private void emitPeriodicWatermark(SourceOutput<T> splitOutput) {
  if (splitOutput == null) {
    return;
  }

  if (splitOutput instanceof SourceOutputWithWatermarks) {
    ((SourceOutputWithWatermarks<T>) splitOutput).emitPeriodicWatermark();
    return;
  }

  // splitOutput is an internal Flink type (e.g. SplitLocalOutput from
  // ProgressiveTimestampsAndWatermarks) that does not expose
  // SourceOutputWithWatermarks publicly. The reader-level call below is
  // semantically equivalent: it iterates all registered split outputs
  // (this split is still registered until internal.releaseOutputForSplit()
  // returns) and flushes the combined periodic watermark.
  watermarkOutput.emitPeriodicWatermark();
}

This removes the setAccessible(true) call which is exactly the JDK-17 blocker this PR aims to fix.

[xxubai]

Thanks, good point. I removed the reflection fallback and simplified it to use watermarkOutput.emitPeriodicWatermark() directly