RFR: 8236264,,Remove jdk.jfr.Recording::setFlushInterval and jdk.jfr.Recording::getFlushInterval

[Erik Gahlin]

Hi,

Could I have review of a fix that will remove some API methods from the 
EventStream API so they will not be part of JDK 14.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8236264

CSR:
https://bugs.openjdk.java.net/browse/JDK-8236265

Webrev:
http://cr.openjdk.java.net/~egahlin/8236264/

Testing:
test/jdk/jdk/jfr

Thanks
Erik