[8u] backport of 8076968 and 8062591

[Igor Veresov]

I’d like to backport:

8062591: SPARC PICL causes significantly longer startup times
JDK9 changeset: http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/aedfc7337448 <http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/aedfc7337448>
JBS: https://bugs.openjdk.java.net/browse/JDK-8062591

8076968: PICL based initialization of L2 cache line size on some SPARC systems is incorrect
JDK9 changeset: http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/7ac058b59e10 <http://hg.openjdk.java.net/jdk9/hs-comp/hotspot/rev/7ac058b59e10>
JBS: https://bugs.openjdk.java.net/browse/JDK-8076968


The changes required a little bit of tweaking compared to jdk9, but nothing significant. 
The reason I want to backport 8062591 is to make 8076968 apply cleanly since it touches the same code.


Thanks!
igor