RFR(S) 8204557: NMT: Linux os::committed_in_range() does not break out outer loop when contiguous region is found

[Zhengyu Gu]

Thomas found this bug while in discussion of JDK-8202772 [1]

When contiguous committed region is found, it only breaks out inner 
loop. Instead of returning the found range, it continues scanning the 
rest to the end.

As the result, it squeezes all committed regions into one, even there 
are holes.

Bug: https://bugs.openjdk.java.net/browse/JDK-8204557
Webrev: http://cr.openjdk.java.net/~zgu/8204557/webrev.00/

Test:

   hotspot_nmt and gtest on Linux x64 (fastdebug and release)
   Submit test also came back clean.

[1] 
http://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2018-June/028419.html


Thanks,

-Zhengyu