Fix state exit with fork

- Fix a case where state leading into a fork
  doesn't exit.
- Relates to work in #221

spring-statemachine-build-tests/src/test/java/org/springframework/statemachine/buildtests/ForkJoinEntryExitTests.java

@@ -81,6 +81,8 @@ public class ForkJoinEntryExitTests extends AbstractBuildTests {
 					.step().expectState("S1").and()
 					.step()
 						.sendEvent("E1")
+						.expectStateEntered(3)
+						.expectStateExited(1)
 						.expectStates("S2", "S210", "S220").and()
 					.step()
 						.sendEvent("E2")
@@ -109,8 +111,10 @@ public class ForkJoinEntryExitTests extends AbstractBuildTests {
 					.step().expectState("S1").and()
 					.step()
 						.sendEvent("E1")
+						.expectStateEntered(3)
+						.expectStateExited(1)
 						.expectStates("S2", "S210", "S220").and()
-						.step()
+					.step()
 						.sendEvent("E2")
 						.expectStateEntered(1)
 						.expectStateExited(1)