RFR 8231264: Disable biased-locking and deprecate all flags related to biased-locking

[Florian Weimer]

* Andrew Haley:

> On 11/27/19 10:30 PM, Florian Weimer wrote:
>> If biased locking were determined important to JNI code, it would be
>> interesting to consider how its performance gains relate to the
>> general JNI overhead.
>
> JNI overhead is significant, partly because of the need for the
> VM-native state changes to be atomic. I don't think a couple of CAS
> operations will make a large difference.

I see.  Is critical JNI still unsupported?

It's also not clear that synchronization around JNI is common outside
the JDK itself.