RFR: Fix held_monitor_count calculation

[Hui Shi]

On Tue, 15 Jun 2021 08:57:33 GMT, Rickard Bäckman <rbackman at openjdk.org> wrote:

>> Problem and fixes includes and we (Tencent team) would like to fixing further related issues.
>> 
>> - C1/C2 locking when deoptimize happen might lost counter inc.
>>   -  increase held monitor count in JIT code slow path runtime method  (Runtime1::monitorenter/SharedRuntime::complete_monitor_locking_C_inc_held_monitor_count),
>>   - JIT code only increases held monitor count for fastpath.
>> - Deoptimization::relock_objects should update count in deoptee thread instead of current rhead.
>> - Add missing dec_held_monitor_count in interpreter.
>> - Enable assert ion in runtime dec_held_monitor_count and no assert triggers.
>> - Assert when Thread assert held_monitor_count should be zero.
>>    - No assertion happens with above fixes.
>
> Looks good to me, I think Ron wants to have a look as well.

@rickard @pron  Thanks for your review!

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PR: https://git.openjdk.java.net/loom/pull/47