hg: jdk/sandbox: JDK-8246436-branch: Fix warning + cleanup

[erik.gahlin at oracle.com]

Changeset: 0d35d7d1db6e
Author:    egahlin
Date:      2020-06-17 13:07 +0200
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/0d35d7d1db6e

JDK-8246436-branch: Fix warning + cleanup

! make/CompileToolsHotspot.gmk
! make/hotspot/gensrc/GensrcJfr.gmk
! make/modules/jdk.jfr/Gendata.gmk
! make/src/classes/build/tools/jfr/GenerateJfrFiles.java