RFR (XS): 8193105: Print error code when map_memory_to_file() fails

[sangheon.kim]

Hi all,

Could I have some reviews for this change?

JDK-8190308 (Implementation: JEP 316: Heap Allocation on Alternative 
Memory Devices) introduced a new test(TestAllocateHeapAt.java) but it is 
failing on Solaris-Sparc with fastdebug build. But unfortunately there's 
no error print when related function fails.

This proposal is simply adding error code print for further 
investigation of JDK-8192871(TestAllocateHeapAt fails), not change its 
logic.

CR: https://bugs.openjdk.java.net/browse/JDK-8193105
Webrev: http://cr.openjdk.java.net/~sangheki/8193105/webrev.0
Testing: hs-tier1

Thanks,
Sangheon