[10] RFR(XS) 8185802: Enable AVX3 by default

[Vladimir Kozlov]

https://bugs.openjdk.java.net/browse/JDK-8185802

JDK-8183103 fix in JDK 9 disable AVXV3 by default (it set UseAVX to 2 by 
default). Now that fix was pushed into JDK 10 which disables AVX3 
testing. Enable AVX3 again.

src/cpu/x86/vm/globals_x86.hpp
@@ -116,7 +116,7 @@
    product(bool, UseStoreImmI16, true, 
      \
            "Use store immediate 16-bits value instruction on x86") 
      \
 
      \
-  product(intx, UseAVX, 2, 
     \
+  product(intx, UseAVX, 3, 
     \
            "Highest supported AVX instructions set on x86/x64") 
      \
            range(0, 99) 
      \
 
      \


Thanks,
Vladimir