Review request: 8024650: Don't adjust MaxMetaspaceSize up to MetaspaceSize

[Stefan Karlsson]

http://cr.openjdk.java.net/~stefank/8024650/webrev.00/

- Limit MetaspaceSize to MaxMetaspaceSize
- Make sure we don't align down to 0.
- jtreg test

Note that this patch also adds/changes some functionality in the 
OutputAnalyzer in test/testlibrary.

thanks,
StefanK