Remove legacy path for Go Dataflow post commits. (#27994)

* Remove legacy path for Go Dataflow post commits.

* Fix typo.

* Observation: xlang tests aren't run in the Go Dataflow suite.

---------

Co-authored-by: lostluck <13907733+lostluck@users.noreply.github.com>

build.gradle.kts

@@ -448,18 +448,7 @@ tasks.register("goPostCommitDataflowARM") {
 }
 
 tasks.register("goPostCommit") {
-  dependsOn(":goIntegrationTests")
-}
-
-tasks.register("goIntegrationTests") {
-  doLast {
-    exec {
-      executable("sh")
-      args("-c", "./sdks/go/test/run_validatesrunner_tests.sh --runner dataflow")
-    }
-  }
-  dependsOn(":sdks:go:test:build")
-  dependsOn(":runners:google-cloud-dataflow-java:worker:shadowJar")
+  dependsOn(":sdks:go:test:dataflowValidatesRunner")
 }
 
 tasks.register("playgroundPreCommit") {

sdks/go/test/build.gradle

@@ -28,15 +28,10 @@ task dataflowValidatesRunner() {
   group = "Verification"
 
   dependsOn ":sdks:go:test:goBuild"
-  dependsOn ":sdks:java:testing:expansion-service:buildTestExpansionServiceJar"
 
   doLast {
-    def pipelineOptions = [  // Pipeline options piped directly to Go SDK flags.
-        "--expansion_jar=test:${project(":sdks:java:testing:expansion-service").buildTestExpansionServiceJar.archivePath}",
-    ]
     def options = [
         "--runner dataflow",
-        "--pipeline_opts \"${pipelineOptions.join(' ')}\"",
     ]
     exec {
       executable "sh"
@@ -51,11 +46,9 @@ task dataflowValidatesRunnerARM64() {
   group = "Verification"
 
   dependsOn ":sdks:go:test:goBuild"
-  dependsOn ":sdks:java:testing:expansion-service:buildTestExpansionServiceJar"
 
   doLast {
     def pipelineOptions = [  // Pipeline options piped directly to Go SDK flags.
-        "--expansion_jar=test:${project(":sdks:java:testing:expansion-service").buildTestExpansionServiceJar.archivePath}",
         "--machine_type=t2a-standard-1",
     ]
     def options = [