Due to a change in behavior between ant 1.8.2 and ant 1.10.5, the ant `jfx.release.suffix` property contains the literal double-quote characters on Mac and Linux rather than the intended empty string when running with `gradle -PMILESTONE_FCS=true ...`

This doesn't affect the production builds, but we do have a closed build task that use this variable as a filename suffix. Those files now have the literal double-quotes in their name which is not intended.

This was originally discovered in an FX 8 build, but I confirmed that the same bug is present in jfx-dev.