RFR: 8170737: Not enough old space utilisation

[Michail Chernov]

Hi,

Could I have a reviews for this change, please?

http://cr.openjdk.java.net/~mchernov/8170737/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8170737

Test fails because Runtime.maxMemory() results depends on the heap size 
shrinking. So need to calculate the expected heap occupation before a 
garbage allocation. Tests were updated accordingly. Also 
GcProvokerImpl.java was removed because it was not removed on previous 
commit by mistake.
Tested via RBT.

Thanks,
Michail