RFR: 8246196: javax/management/MBeanServer/OldMBeanServerTest fails with AssertionError

[Daniil Titov]

Please review change [1] that fixes an intermittent  failure of the test when it is runs with -Xcomp.

The problem here is that the timespan the test uses to count notifications  is not adjusted for "test.timeout.factor" system property.

The original issue is reproducible in JDK 11 and on Solaris platform only. However,  I think it makes sense to apply this change in JDK 15 to prevent this from possible happening in the future and then backport it to 11.

[1] http://cr.openjdk.java.net/~dtitov/8246196/webrev.01/
[2] https://bugs.openjdk.java.net/browse/JDK-8246196

Thank you,
Daniil