Approve backport of test bug

[Mattias Tobiasson]

Hi,
Please approve this testbug backport from 9. The patch applies cleanly.

The original bug is marked as a jigsaw bug, but that is only because it
was discovered in jigsaw builds. The test bug is general and may fail in
any build. It currently fails when Resource Manager is enabled.

The problem is that the assumes that it can always transform a few standard
java io classes when they are loaded. This does not work if those classses
have already been used by the jvm before the test is started.

The test has also been improved to verify that the correct methods are
transformed (with the correct signature, not just the corect name).

Bug:
https://bugs.openjdk.java.net/browse/JDK-8060165

Changeset:
http://closedjdk.us.oracle.com/jdk9/dev/jdk/test/closed/rev/a6d1b2022b93

Review thread:
https://java.se.oracle.com/code/cru/CR-JDK9DEV-618

Thanks,
Mattias