Stop running RunnableOnService tests in the Core SDK

With the direct runner executing all of this category (in
runners/direct-java), we maintain this test coverage without running
these tests while building the Core SDK.

Required to remove the legacy direct runner.

Author: tgroh

sdks/java/core/pom.xml

@@ -124,6 +124,16 @@
         <artifactId>maven-compiler-plugin</artifactId>
       </plugin>
 
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <configuration>
+          <excludedGroups>
+            org.apache.beam.sdk.testing.RunnableOnService
+          </excludedGroups>
+        </configuration>
+      </plugin>
+
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-dependency-plugin</artifactId>