[8u] RFR 8158871: Long response times with G1 and StringDeduplication

[Vladimir Kempik]

Hello

Please review this backport of 8158871 to jdk8u.

Few changes for jdk8 were applied:

1) universall logging call changed to gclog_or_tty->print_cr

2) added casting of multiplication result (size_t * double) to size_t 
because on macosx platform the result was casted to double:

  _entry_cache = new G1StringDedupEntryCache((size_t)(_min_size * 
_max_cache_factor));
...
  _entry_cache->set_max_size((size_t)(size * _max_cache_factor));




Testing: jprt

Bug: https://bugs.openjdk.java.net/browse/JDK-8158871
Webrev: http://cr.openjdk.java.net/~vkempik/8158871/webrev.00/

Thanks
-Vladimir