RFR (M): 8219748: Add and use getter for the timing object in G1

[Thomas Schatzl]

Hi,

  can I have reviews that adds a "phase_times()" getter to
G1CollectedHeap to avoid the 50+ times of using "policy()-
>phase_times()" instead?

CR:
https://bugs.openjdk.java.net/browse/JDK-8219748
Webrev:
http://cr.openjdk.java.net/~tschatzl/8219748/webrev/
Testing:
local compilation

Thanks,
  Thomas