chore: Skip generating test jar for BOM (#1899)

* chore: Don't generate testlib for parent and bom

* chore: Add in properties per project

* chore: Move testlib configs to modules

* chore: Don't skip child modules

* chore: Remove jar plugin in bom

* chore: Skip test jar classifier for BOM

Author: lqiu96

gax-bom/pom.xml

@@ -84,6 +84,20 @@
           <skip>true</skip>
         </configuration>
       </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jar-plugin</artifactId>
+        <executions>
+          <execution>
+            <goals>
+              <goal>test-jar</goal>
+            </goals>
+            <configuration>
+              <skip>true</skip>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
     </plugins>
   </build>
 </project>