Make service lifecycle checks thread safe

Make service lifecycle checks thread safe

RunLoop tests were getting wedged trying to communicate with the vm-isolate that was shutdown before a test isolate started up. dartbug.com/22219

This CL:
* ensures that any 'is the service running' checks are done with a lock held.
* Normalizes trace messages printed from the vm-service.

Committed: https://code.google.com/p/dart/source/detail?r=43348

[Cutch, 2015-01-30 20:15:34]

johnmccutchan@google.com changed reviewers:
+ asiva@google.com

[Cutch, 2015-01-30 22:02:58]

On 2015/01/30 20:24:21, Cutch wrote:

TBR

[Cutch, 2015-01-30 22:03:26]

Committed patchset #3 (id:40001) manually as 43348 (presubmit successful).

[siva, 2015-01-31 00:22:11]

Can you post the backtrace of the thread that was stuck.
Some of the code here seems to only be run by the service isolate so it is not
clear.