RFR (S): 8204082: Make names of Young GCs more uniform in logs

[Thomas Schatzl]

Hi all,

  another round of reviews after some more internal remarks :P

I also changed the title of the CR.

The set of "final" tags would be:

Pause Young (Normal) ...
Pause Young (Concurrent Start) ...
Pause Young (Concurrent End) ...
Pause Young (Mixed) ...

I also adapted the strings in the GCVerifyType functionality.

http://cr.openjdk.java.net/~tschatzl/8204082/webrev.1_to_2 (diff)
http://cr.openjdk.java.net/~tschatzl/8204082/webrev.2 (full)

Testing:
running through all gc tests locally

Thanks,
  Thomas