RFR: [11u] 8217368: AArch64: C2 recursive stack locking optimisation not triggered

[Nick Gasson]

Hi Andrew,

> 
> 2) The upstream change includes a modification to LockUnlock.java in the
> micro test suite extending that test so it exercises this patch. This
> part of the change set has been omitted because the micro test suite has
> not been backported to jdk11u (again for good reason).
> 

I just ran the micro benchmark on 11u with and without your backport 
patch to confirm it fixes the performance problem. Looks good!

Thanks,
Nick