[8u] [jfr] RFR 8230707: JFR related tests are failing

[Jaroslav Bachorík]

JIRA:      https://bugs.openjdk.java.net/browse/JDK-8230707
Webrev: http://cr.openjdk.java.net/~jbachorik/8230707/

Please, review this test-only change to JFR related tests which were
brought in as a part of the JFR backport effort. Due to differences in GC,
runtime, compiler, etc. implementations between JDK 8 and JDK 9+ some tests
need updating or complete removal.

The most significant differences:
- no segmented code cache
- no G1 IHOP
- G1 emits serial old event instead G1 full
- no CI and compilation directives
- no unified logging

The changes are usually quite trivial (removing the offending JVM arg or
removing test relying on non-existent features).

With these changes in place all jdk_jfr tests are passing.

Cheers,

-JB-