RFR(XXS): 8185884 NMT: taskqueues are miscategorized to mtClass

[Zhengyu Gu]

Hi,

Please review this small change, which corrects memory type of taskqueue 
from mtClass to mtGC.

Bug: https://bugs.openjdk.java.net/browse/JDK-8185884
Webrev: http://cr.openjdk.java.net/~zgu/8185884/webrev.00/


Test:
hotspot_tier1_runtime: Linux x64 release build



Thanks,

-Zhengyu