Cannot build JavaFX with OpenJDK due to dependency on jdk.jfr

After the fix for JDK-8161704, we can no longer build JavaFX with OpenJDK due to leftover dependency on jdk.jfr.

The build logic that depends on jfr is currently disabled in build.gradle, but the module-info.java of javafx.base has a "requires jdk.jfr" statement. This should be removed. As a note, JDK-8088418 is a follow-on RFE to switch to the new API, and when/if that is done it will need to be done such that the dependency is optional.