RFR(s): 8247248: JVM TI might create JNI locals in another thread when using handshakes.

[Robbin Ehn]

Hi David and Serguei, (Dan feel free to chime in)

> Honestly I think I'd like to see things reverted to the use of calling_thread as done for the VMOperation previously. We 
> know it is functionally correct and it should also have the same performance profile.

Done:
http://cr.openjdk.java.net/~rehn/8247248/v2/webrev/

Passes: hotspot jdi/jvmti testing, running mach5.

I'll push tomorrow morning if test is ok and you all are happy (+- nits). (and no objection to break the 24h rule)
I started this patch with reverting "8242425: JVMTI monitor operations should use Thread-Local Handshakes".
And work my way forward.

Thanks, Robbin

> 
> Thanks,
> David
> 
>> Thanks, Robbin
>>
>>>
>>> Thanks,
>>> David
>>> -----
>>>
>>>> Issue:
>>>> https://bugs.openjdk.java.net/browse/JDK-8247248
>>>>
>>>> Local testing of JDI/JVMTI and t1-5.
>>>> (no real crash so there is nothing to reproduce)
>>>>
>>>> Thanks, Robbin