use Java 17 harness (#39570)

* use Java 17 harness

* update comment

Author: aIbrahiim

.github/trigger_files/beam_PostCommit_Python_Xlang_IO_Dataflow.json

@@ -1,4 +1,4 @@
 {
   "comment": "Modify this file in a trivial way to cause this test suite to run",
-  "modification": 2
+  "modification": 3
 }

sdks/python/test-suites/dataflow/common.gradle

@@ -671,6 +671,8 @@ project.tasks.register("inferencePostCommitITPy312") {
 // Create cross-language tasks for running tests against Java expansion service(s)
 def gcpProject = project.findProperty('gcpProject') ?: 'apache-beam-testing'
 def gcpRegion = project.findProperty('gcpRegion') ?: 'us-central1'
+// Default to the minimum required Java version (currently bounded by IcebergIO which needs Java 17+)
+def javaHarnessVersion = project.findProperty('testJavaVersion') ?: '17'
 
 project(":sdks:python:test-suites:xlang").ext.xlangTasks.each { taskMetadata ->
     createCrossLanguageUsingJavaExpansionTask(
@@ -682,7 +684,7 @@ project(":sdks:python:test-suites:xlang").ext.xlangTasks.each { taskMetadata ->
         "--project=${gcpProject}",
         "--region=${gcpRegion}",
         "--sdk_container_image=gcr.io/apache-beam-testing/beam-sdk/beam_python${project.ext.pythonVersion}_sdk:latest",
-        "--sdk_harness_container_image_overrides=.*java.*,gcr.io/apache-beam-testing/beam-sdk/beam_java11_sdk:latest"
+        "--sdk_harness_container_image_overrides=.*java.*,gcr.io/apache-beam-testing/beam-sdk/beam_java${javaHarnessVersion}_sdk:latest"
       ],
       pytestOptions: basicPytestOpts,
       additionalDeps: taskMetadata.additionalDeps,