Reinstate testing of Jetty JSP sample on Java 9

See gh-10456

Author: wilkinsona

spring-boot-samples/spring-boot-sample-jetty-jsp/pom.xml

@@ -82,23 +82,4 @@
 			</plugin>
 		</plugins>
 	</build>
-	<profiles>
-		<profile>
-			<id>java9</id>
-			<activation>
-				<jdk>9</jdk>
-			</activation>
-			<build>
-				<plugins>
-					<plugin>
-						<groupId>org.apache.maven.plugins</groupId>
-						<artifactId>maven-surefire-plugin</artifactId>
-						<configuration>
-							<skipTests>true</skipTests>
-						</configuration>
-					</plugin>
-				</plugins>
-			</build>
-		</profile>
-	</profiles>
 </project>