Happy birthday Java 26! - #2076

### What changes were proposed in this pull request?

This PR aims to upgrade `JaCoCo` to 0.8.16.

- `gradle/libs.versions.toml`: `jacoco` 0.8.14 -> 0.8.16
- `gradle/verification-metadata.xml`: regenerated from scratch. Only the JaCoCo artifacts and their ASM dependencies (`asm`, `asm-bom`, `asm-commons`, and `asm-tree`, 9.9 -> 9.11.1) changed.

### Why are the changes needed?

To support the JDK 27 test toolchain officially and remove the JaCoCo agent exceptions from the unit test output.

JaCoCo 0.8.14 cannot read class files of major version 71, so it logs `IllegalClassFormatException` caused by `Unsupported class file major version 71` while instrumenting JDK classes (e.g. `java.net.http`, `jdk.httpserver`, and `sun.security.pkcs11`) and classes generated by Mockito. The tests still pass, but the output contains hundreds of stack traces.

- [JaCoCo 0.8.16](https://github.com/jacoco/jacoco/releases/tag/v0.8.16) (2026-10-26)
  - Official support for Java 27 ([#2287](jacoco/jacoco#2287))
  - Experimental support for Java 28 class files ([#2170](jacoco/jacoco#2170), [#2189](jacoco/jacoco#2189))
  - Classes loaded by the platform class loader are instrumented only with the agent option `inclbootstrapclasses=true` ([#2155](jacoco/jacoco#2155))
  - ASM 9.11.1 ([#2299](jacoco/jacoco#2299), [#2304](jacoco/jacoco#2304))
- [JaCoCo 0.8.15](https://github.com/jacoco/jacoco/releases/tag/v0.8.15) (2026-06-05)
  - Official support for Java 26 ([#2076](jacoco/jacoco#2076))
  - Experimental support for Java 27 class files ([#2004](jacoco/jacoco#2004))
  - ASM 9.10.1 ([#2134](jacoco/jacoco#2134))

### Does this PR introduce _any_ user-facing change?

No. JaCoCo is used only for the unit tests and is not included in the operator distribution.

### How was this patch tested?

Pass the CIs. In addition, the following passed locally on the JDK 27 test toolchain.

```bash
gradle cleanTest build jacocoTestReport spotlessCheck --refresh-dependencies
```

The number of `Unsupported class file major version 71` occurrences in `<module>/build/test-results/test/*.xml` was measured before and after this PR.

| Module | Before (0.8.14) | After (0.8.16) | Tests |
|---|---|---|---|
| `spark-operator-api` | 0 | 0 | 66 |
| `spark-submission-worker` | 1 | 0 | 40 |
| `spark-operator` | 359 | 0 | 692 |

All 798 tests passed, and the coverage totals of `jacocoTestReport` are identical before and after this PR in all three modules.

### Was this patch authored or co-authored using generative AI tooling?

Generated-by: Claude Opus 5.5

Closes #992 from dongjoon-hyun/SPARK-60815.

Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>