[KYUUBI #7352] Skip Java 8 tests for Spark engine

### Why are the changes needed?

Remove Java 8 and keep only Java 17 tests for the Spark engine. We have `-release 8` guard, so it should be low risk.

This reduces the ASF CI resource usage.

### How was this patch tested?

Review.

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

No.

Closes #7352 from pan3793/skip-8.

Closes #7352

a925c5e [Cheng Pan] Skip Java 8 tests for Spark engine

Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>

Author: pan3793

.github/workflows/master.yml

@@ -49,7 +49,6 @@ jobs:
       max-parallel: 6
       matrix:
         java:
-          - 8
           - 17
         python:
           - '3.9'