RFR(trivial): 8223359: JDK-8221359 breaks TestG1ParallelPhases.java

[Kim Barrett]

Please review this trivial update to the jfr test
TestG1ParallelPhases.java, to account for the recent removal of the SATB
filtering phase by JDK-8221359.  The test should no longer expect an
event for that phase.

CR:
https://bugs.openjdk.java.net/browse/JDK-8223359

Webrev:
http://cr.openjdk.java.net/~kbarrett/8223359/open.00/

Testing:
Locally (linux-x64) reproduced the failure, and verified the change eliminated the failure.