RFR(XXS) 8190729: Adjustment to anonymous metadata space chunk allocation algorithm

[Zhengyu Gu]

Hi,

To follow up recent discussion of anonymous metadata space memory usage, 
I would like submit this simple fix for review.

By continuing allocating anonymous metadata space from SpecializeChunk 
pool, up to 4 chunks, it reduces the waste from 60+% to about 30%.


Bug: https://bugs.openjdk.java.net/browse/JDK-8190729
Webrev: http://cr.openjdk.java.net/~zgu/8190729/webrev.00/

Test:

   hotspot_tier1_runtime on Linux x64 (fastdebug and release)


Thanks,

-Zhengyu