Run Flink and Spark3 tests on Java 17 too

Project supports building with 8, 11 and 17. In most CI scripts we run
the jobs on all supported Java versions, let's do same here to ensure
the build would work locally too.

.github/workflows/flink-ci.yml

@@ -71,8 +71,12 @@ jobs:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
-        jvm: [8, 11]
+        jvm: [8, 11, 17]
         flink: ['1.17', '1.18', '1.19']
+        excludes:
+          # Flink 1.17 does not support Java 17.
+          - jvm: 17
+            flink: '1.17'
     env:
       SPARK_LOCAL_IP: localhost
     steps:

.github/workflows/spark-ci.yml

@@ -69,7 +69,7 @@ jobs:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
-        jvm: [8, 11]
+        jvm: [8, 11, 17]
         spark: ['3.3', '3.4', '3.5']
     env:
       SPARK_LOCAL_IP: localhost
@@ -102,6 +102,7 @@ jobs:
     runs-on: ubuntu-22.04
     strategy:
       matrix:
+        # 17 exercised by spark-3x-java-17-tests
         jvm: [8, 11]
         spark: ['3.3','3.4','3.5']
     env: