RFR(XXS) 8201542: Remove unused _gc_timer field in GCMemoryManager

[Aleksey Shipilev]

On 04/30/2018 05:32 PM, Zhengyu Gu wrote:
> Please review this trivial cleanup to remove unused _gc_timer in GCMemoryManager.
> 
> Bug: https://bugs.openjdk.java.net/browse/JDK-8201542
> Webrev: http://cr.openjdk.java.net/~zgu/8201542/webrev.00/

Looks good to me.

-Aleksey