After the openjfx/12-dev repo is forked from jfx-dev, we need to change the release version to 13 in JavaFX jfx-dev for OpenJFX 13.

We need to update the release values in the following file:

build.properties

Additionally, since this bumps the major version we need to update the following unit test:

modules/javafx.base/src/test/java/test/com/sun/javafx/runtime/VersionInfoTest.java