EAP 6 start up stalls on EJB creation

Issue

• JBoss stalls during start up, with MSC threads stuck creating an EJB:

"MSC service thread 1-1" prio=10 tid=0x00007fd19464d800 nid=0xa9a in Object.wait() [0x00007fd18d631000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x000000009df05b00> (a org.jboss.as.ejb3.component.stateless.StatelessSessionComponent)
    at java.lang.Object.wait(Object.java:503)
    at org.jboss.as.ee.component.BasicComponent.waitForComponentStart(BasicComponent.java:109)
    - locked <0x000000009df05b00> (a org.jboss.as.ejb3.component.stateless.StatelessSessionComponent)
    at org.jboss.as.ee.component.BasicComponent.constructComponentInstance(BasicComponent.java:127)
    at org.jboss.as.ee.component.BasicComponent.createInstance(BasicComponent.java:85)
    at org.jboss.as.ejb3.component.stateless.StatelessSessionComponent$1.create(StatelessSessionComponent.java:67)
    at org.jboss.as.ejb3.component.stateless.StatelessSessionComponent$1.create(StatelessSessionComponent.java:64)
    at org.jboss.as.ejb3.pool.AbstractPool.create(AbstractPool.java:60)
    at org.jboss.as.ejb3.pool.strictmax.StrictMaxPool.get(StrictMaxPool.java:123)

• Application are not started correctly if there are multiple SingletonServices, the server hung with the following thread

"MSC service thread 1-1" prio=10 tid=0x00007ff3b04a5000 nid=0x40a0 in Object.wait() [0x00007ff399ad6000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000c92d4100> (a org.jboss.as.ejb3.component.singleton.SingletonComponent)
    at java.lang.Object.wait(Object.java:503)
    at org.jboss.as.ee.component.BasicComponent.waitForComponentStart(BasicComponent.java:117)
    - locked <0x00000000c92d4100> (a org.jboss.as.ejb3.component.singleton.SingletonComponent)
    at org.jboss.as.ee.component.BasicComponent.constructComponentInstance(BasicComponent.java:147)
    at org.jboss.as.ee.component.BasicComponent.constructComponentInstance(BasicComponent.java:135)
    at org.jboss.as.ee.component.BasicComponent.createInstance(BasicComponent.java:90)
    at org.jboss.as.ejb3.component.singleton.SingletonComponent.getComponentInstance(SingletonComponent.java:122)
    - locked <0x00000000c92d43a8> (a java.lang.Object)
    at org.jboss.as.ejb3.component.singleton.SingletonComponentInstanceAssociationInterceptor.processInvocation(SingletonComponentInstanceAssociationInterceptor.java:47)