Dump diagnostics (Coroner's Report) if a test takes too long. Fixes #3110

All tests set to 60 seconds, except DefaultSchedulerSpec which is set to 5 minutes.

Example dump:

````
Coroner's Report for akka.actor.ActorLookupSpec
Test took longer than 1000ms to finish. Is the patient deceased?
OS Architecture: x86_64
Available processors: 8
System load (last minute): 0.6064453125
VM start time: Thu Feb 28 14:12:50 NZDT 2013
VM uptime: 4162394ms
Heap usage: init = 536870912(524288K) used = 758384712(740610K) committed = 1502085120(1466880K) max = 1502085120(1466880K)
Non-heap usage: init = 24313856(23744K) used = 257187320(251159K) committed = 358875136(350464K) max = 452984832(442368K)
"ActorLookupSpec-akka.actor.default-dispatcher-2" Id=5787 WAITING on akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinPool@1588ffae
	at sun.misc.Unsafe.park(Native Method)
	-  waiting on akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinPool@1588ffae
	at scala.concurrent.forkjoin.ForkJoinPool.scan(ForkJoinPool.java:1594)
	at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1478)
	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:104)


"ActorLookupSpec-akka.actor.default-dispatcher-3" Id=5788 TIMED_WAITING on akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinPool@1588ffae
	at sun.misc.Unsafe.park(Native Method)
	-  waiting on akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinPool@1588ffae
	at scala.concurrent.forkjoin.ForkJoinPool.idleAwaitWork(ForkJoinPool.java:1626)
	at scala.concurrent.forkjoin.ForkJoinPool.scan(ForkJoinPool.java:1579)
	at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1478)
	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:104)


"ActorLookupSpec-akka.actor.default-dispatcher-4" Id=5789 WAITING on akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinPool@1588ffae
	at sun.misc.Unsafe.park(Native Method)
	-  waiting on akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinPool@1588ffae
	at scala.concurrent.forkjoin.ForkJoinPool.scan(ForkJoinPool.java:1594)
	at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1478)
	at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:104)


"ActorLookupSpec-scheduler-1" Id=5786 TIMED_WAITING
	at java.lang.Thread.sleep(Native Method)
	at akka.actor.LightArrayRevolverScheduler.waitNanos(Scheduler.scala:226)
	at akka.actor.LightArrayRevolverScheduler$$anon$13.nextTick(Scheduler.scala:391)
	at akka.actor.LightArrayRevolverScheduler$$anon$13.run(Scheduler.scala:370)
	at java.lang.Thread.run(Thread.java:722)

...
````