Publish SI test binder jar as a maven artifact

- spring-cloud-stream module will build a new test-jar called spring-cloud-stream-<version>-test-binder.jar
 - This artifact contains all the classes from the package org/springframework/cloud/stream/binder/integration/
   in test source for spring-cloud-stream

pom.xml

@@ -89,6 +89,14 @@
                 <artifactId>objenesis</artifactId>
                 <version>${objenesis.version}</version>
             </dependency>
+            <dependency>
+                <groupId>org.springframework.cloud</groupId>
+                <artifactId>spring-cloud-stream</artifactId>
+                <version>${project.version}</version>
+                <type>test-jar</type>
+                <scope>test</scope>
+                <classifier>test-binder</classifier>
+            </dependency>
         </dependencies>
     </dependencyManagement>
     <modules>

spring-cloud-stream/pom.xml

@@ -63,4 +63,27 @@
 		</dependency>
 	</dependencies>
 
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-jar-plugin</artifactId>
+				<version>3.0.2</version>
+				<executions>
+					<execution>
+						<configuration>
+							<includes>
+								<include>**/integration/*</include>
+							</includes>
+							<classifier>test-binder</classifier>
+						</configuration>
+						<goals>
+							<goal>test-jar</goal>
+						</goals>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+
 </project>