hg: build-infra/jdk9/hotspot: Move JVM_CFLAGS_WARNINGS to configure.

[magnus.ihse.bursie at oracle.com]

Changeset: 59d8c6dd75fb
Author:    ihse
Date:      2016-01-15 15:34 +0100
URL:       http://hg.openjdk.java.net/build-infra/jdk9/hotspot/rev/59d8c6dd75fb

Move JVM_CFLAGS_WARNINGS to configure.

! makefiles/Common.gmk
! makefiles/Dtrace.gmk
! makefiles/JvmPlatforms.gmk