RFR: 8150183: gc/g1/plab/TestPLABResize.java - previous PLAB size should be less than current

[Michail Chernov]

Hello,

Please review this fix for gc/g1/plab/TestPLABResize.java test.

Webrev: http://cr.openjdk.java.net/~mchernov/8150183/webrev.00/
Bug: https://bugs.openjdk.java.net/browse/JDK-8150183

This test tries to check resizing PLAB. PLAB desired size calculation 
does not depend on number of GC thread, AppPLABResize.java was fixed.
Also checking of PLAB sizes was made less strict because we cannot 
expect that PLAB will change exactly as amount of promoted bytes. Now 
test checks only start and end values of test iteration.

This was checked on a lot of VM options combination used in nightly.

PS: Sorry for duplicate of message.

Thanks
Michail