RFR: JDK-8141037: Remove _MARKING_VERBOSE_ from the G1 code

[Bengt Rutisson]

Hi everyone,

This is a fix, which is very similar to "JDK-8140781: Remove 
_MARKING_STATS_ from the G1 code".

http://cr.openjdk.java.net/~brutisso/8141037/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8141037

The _MARKING_VERBOSE_ define is used in the code to log more detailed 
information about the marking cycle. Since this is a define that 
requires re-compilation to have any effect the code is not used by 
normal builds.

Thus, this is to be considered debug code. As such it should be removed 
from the normal code base and included back if it is needed for a debug 
session.

The change also removes the dead code print_finger().

Thanks,
Bengt