RFR (S): 8024634 - gc/startup_warnings tests can fail due to unrelated warnings

[Per Liden]

Hi,

Could I please have a couple of reviews on this small test fix.

http://cr.openjdk.java.net/~pliden/8024634/webrev.01/

https://bugs.openjdk.java.net/browse/JDK-8024634

Summary: Some tests check that no warnings are printed when a specific 
GC is used. These test are a bit too generic and can catch and fail on 
all sorts of non-GC related warnings. What we actually want to test is 
that we don't print any message about these GCs being deprecated (as is 
the case for some other GC combinations). This isn't exactly bullet 
proof either since some non-GC component could print something 
containing "deprecated", but if that starts to become a problem we'll 
have to reconsider the usefulness of these tests.

Testing: Have run the jtreg tests for GC

cheers,
/Per