RFR: 8152632: Rename LogHandle(...) to Log(...)

[Stefan Karlsson]

Hi all,

Please review this patch to rename the LogHandle macro to Log.

http://cr.openjdk.java.net/~stefank/8152632/webrev.01
https://bugs.openjdk.java.net/browse/JDK-8152632

The main motivation for this patch is to reuse the LogHandle name for a 
type-erased handle to a log instance (JDK-8152711).

Thanks,
StefanK