test: stop RQTT runs from clashing (#5426)

Ensures each RQTT run uses a unique state directory, otherwise parallel runs can interfere with each other.

Co-authored-by: Andy Coates <big-andy-coates@users.noreply.github.com>

ksqldb-functional-tests/src/test/java/io/confluent/ksql/test/rest/RestQueryTranslationTest.java

@@ -21,6 +21,7 @@
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.google.common.collect.ImmutableList;
+import io.confluent.common.utils.TestUtils;
 import io.confluent.ksql.integration.IntegrationTestHarness;
 import io.confluent.ksql.integration.Retry;
 import io.confluent.ksql.rest.server.TestKsqlRestApp;
@@ -71,6 +72,10 @@ public class RestQueryTranslationTest {
 
   private static final TestKsqlRestApp REST_APP = TestKsqlRestApp
       .builder(TEST_HARNESS::kafkaBootstrapServers)
+      .withProperty(
+          KsqlConfig.KSQL_STREAMS_PREFIX + StreamsConfig.STATE_DIR_CONFIG,
+          TestUtils.tempDirectory().getPath()
+      )
       .withProperty(KsqlConfig.KSQL_STREAMS_PREFIX + StreamsConfig.NUM_STREAM_THREADS_CONFIG, 1)
       .withStaticServiceContext(TEST_HARNESS::getServiceContext)
       .build();