8164028: Convert TestPredictions_test to GTest
Reviewed-by: jwilhelm, dfazunen, ehelin

8144690: g1Predictions.hpp includes allocation.inline.hpp
Summary: Remove offending (and unnecessary) include statement.
Reviewed-by: stefank, jmasa

8137082: Factor out G1 prediction code from G1CollectorPolicy and clean up
Summary: Factor out G1 prediction code from G1CollectorPolicy into its own class, constify methods of G1CollectorPolicy and move more implementations to the cpp file.
Reviewed-by: jmasa, sangheki, ecaspole, kbarrett