[8u] 8043899: compiler/5091921/Test7005594.java fails if specified -Xmx is less than 1600m

[Zhengyu Gu]

I would like to backport this patch to 8u for parity with Oracle 8u281.

The original patch does not apply cleanly.

Test7005594.java 8u version does not have @ignore line, so no change 
applied to this file.

The original bug: https://bugs.openjdk.java.net/browse/JDK-8043899
The original patch: 
http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/102506d9d873


8u webrev: http://cr.openjdk.java.net/~zgu/JDK-8043899-8u/webrev.00/

Test:
   Passed Test7005594.java on Linux x86_64

Thanks,

-Zhengyu