INT-3496: JMX Metrics: Int->Long for All `count`

JIRA: https://jira.spring.io/browse/INT-3496

**Cherry-pick to 4.0.x & 3.0.x**

INT-3496: revert `int` methods and introduce `long` methods for `count` metrics

Conflicts:
	spring-integration-jmx/src/main/java/org/springframework/integration/monitor/DirectChannelMetrics.java
	spring-integration-jmx/src/main/java/org/springframework/integration/monitor/PollableChannelMetrics.java
	spring-integration-jmx/src/main/java/org/springframework/integration/monitor/SimpleMessageHandlerMetrics.java
	spring-integration-jmx/src/test/java/org/springframework/integration/jmx/config/ControlBusParserTests.java

Resolved.