Because other databinding bundles already use Java 11.

Change-Id: I6358e6084d442c84f68fa6a26a84bdb70f28e15a
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.ui/+/189168
Tested-by: Platform Bot <platform-bot@eclipse.org>
Reviewed-by: Jens Lideström <jens@lidestrom.se>