RFR (XS): 8212766: TestPromotionEventWithG1.java failed due to "RuntimeException: PLAB size is smaller than object size."

[Thomas Schatzl]

Hi,

  can I have reviews for this change that fixes a bug introduced in
"JDK-8210492 PLAB object promotion events report object sizes in
words"?

In JDK-8210492, for some JFR event, the object size has been changed to
be passed in bytes. However the JFR event gets passed another size, the
PLAB size, which has been forgotten to be fixed accordingly.

So it happens that PLAB size (in words) is compared to object size (in
bytes) which fails if PLAB size happens accidentally to be smaller than
object size.

This change fixes that.

CR:
https://bugs.openjdk.java.net/browse/JDK-8212766
Webrev:
http://cr.openjdk.java.net/~tschatzl/8212766/
Testing:
Test fails with -XX:MinTLABSize=576 -XX:TLABSize=576 without the patch,
passes otherwise.

Thanks,
  Thomas