RFR: JDK-8157141 & JDK-8166454: Solaris getisax(2) and meminfo(2) cleanup

[Alan Burlison]

getisax(2) and meminfo(2) are both Committed interfaces. getisax(2) 
first appeared in Solaris 10, meminfo(2) first appeared in Solaris 9. 
Currently they are both accessed via dlsym(3C) which is unnecessary as 
they will always be present on any version of Solaris that Java9+ will 
run on. In addition, this patch modifies the use of getisax(2) to probe 
for the correct buffer size to use so it will continue to work if/when 
the current 2-word buffer size is exceeded - although of course any 
newly-returned capability bits will need handling, as is already the case.

I'm submitting these two bugs as a single unit for review as they share 
common code (os::Solaris::misc_sym_init()) which can be removed if they 
are fixed together.

getisainfo() manpage:
http://docs.oracle.com/cd/E53394_01/html/E54765/getisax-2.html

meminfo() manpage:
https://docs.oracle.com/cd/E53394_01/html/E54765/meminfo-2.html

Bugs:   https://bugs.openjdk.java.net/browse/JDK-8157141
         https://bugs.openjdk.java.net/browse/JDK-8166454
Webrev: http://cr.openjdk.java.net/~alanbur/JDK-8157141%2bJDK-8166454/

JPRT hostpot testset is clean.

-- 
Alan Burlison
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