hg: jdk/jdk: 8217519: Improve RegMask population count calculation

[claes.redestad at oracle.com]

Changeset: 675d857f5ee3
Author:    redestad
Date:      2019-01-23 10:01 +0100
URL:       http://hg.openjdk.java.net/jdk/jdk/rev/675d857f5ee3

8217519: Improve RegMask population count calculation
Reviewed-by: thartmann, neliasso, kvn

! src/hotspot/share/opto/regmask.cpp
! src/hotspot/share/opto/regmask.hpp
+ src/hotspot/share/utilities/population_count.hpp
+ test/hotspot/gtest/utilities/test_population_count.cpp