RFR(S): 8229254: solaris_x64 build fails

[Boris Ulasevich]

Hi,

Please review the following simple change to make solaris_x64 build 
compilable.

Syntax error was brought by JDK-8191278 [1]. The fix is evident.

Missing constant issue occurred after JDK-8226238 [2]. I copied 
workaround for the case of missing EM_AARCH64 constant in system elf.h 
header from os_linux.cpp implementation.

http://cr.openjdk.java.net/~bulasevich/8229254/webrev.00
http://bugs.openjdk.java.net/browse/JDK-8229254

Testing done: tier1,tier2.

thanks,
Boris

[1] MappedByteBuffer bulk access memory failures are not handled gracefully
 
http://mail.openjdk.java.net/pipermail/hotspot-dev/2019-June/038352.html
[2] Improve error output and fix elf issues in os::dll_load
 
http://mail.openjdk.java.net/pipermail/hotspot-dev/2019-June/038597.html