Benchmarks: make jmh.gradle run cleanly on JDK 17 (module opens, configurable heap, failOnError)

[vaquarkhan]

Problem

The JMH harness fails on a clean JDK 17 checkout:

1. Spark 4.x reflects into sun.util.calendar; without --add-opens the read-path benchmarks throw
   IllegalAccessException at warm-up (stack trace below).
2. Heap is hard-coded to -Xmx32g; the full-scale PlanningBenchmark ...WithStats OOMs at that size.
3. failOnError = true aborts the whole suite (and discards completed results) on one failure.

Reproduce (JDK 17, Corretto 17.0.19)

./gradlew -PsparkVersions=3.5 -PscalaVersion=2.12 \
  :iceberg-spark:iceberg-spark-extensions-3.5_2.12:jmh \
  -PjmhIncludeRegex=IcebergSourceParquetEqDeleteBenchmark \
  -PjmhOutputPath=build/reports/jmh/human.txt \
  -PjmhJsonOutputPath=build/reports/jmh/results.json

=> IllegalAccessException: sun.util.calendar.ZoneInfo

Example failure (from earlier EC2 run):

org.apache.spark.SparkException: Job aborted due to stage failure:
  Task 0 in stage 0.0 failed 1 times ...
java.lang.IllegalAccessException: symbolic reference class is not accessible:
  class sun.util.calendar.ZoneInfo, from interface
  org.apache.spark.sql.catalyst.util.SparkDateTimeUtils (unnamed module)
    at java.base/java.lang.invoke.MemberName.makeAccessException(MemberName.java:955)
    at org.apache.spark.sql.catalyst.util.SparkDateTimeUtils.toJavaDate(SparkDateTimeUtils.scala:304)
    at org.apache.iceberg.spark.source.IcebergSourceBenchmark.appendAsFile(IcebergSourceBenchmark.java:136)

Proposal

Add the JDK 17 --add-opens set to JMH jvmArgs, make heap configurable via -PjmhHeap (default 32g),
and make failOnError configurable via -PjmhFailOnError (default true). One file: jmh.gradle.

Evidence

• Failure: read-path benchmarks crash at warm-up without sun.util.calendar open
• Success: same suites complete on Corretto 17.0.19 / JMH 1.37 on EC2 r7i.4xlarge / r7i.8xlarge when the opens set and a larger heap (-PjmhHeap=220g for full-scale planning) are applied
• Defaults preserved: heap stays 32g and failOnError stays true unless -P flags are passed

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