RFR: 8204173: Lower the minimum number of heap memory pools in MemoryTest.java

[Stefan Karlsson]

Hi all,

Please review this patch to lower the minimum number of heap memory 
pools in MemoryTest.java.

http://cr.openjdk.java.net/~stefank/8204173/webrev.01/
https://bugs.openjdk.java.net/browse/JDK-8204173

Just like the comment in the test says:

 * NOTE: This expected result is hardcoded in this test and this test
 * will be affected if the heap memory layout is changed in
 * the future implementation.
 */

we need to update this test to support ZGC, which only has one heap 
memory pool.

Thanks,
StefanK