The PDEState class is using JavaRuntime.getProvidedVMPackages(...),
which has only been added with version 3.22. But the Manifest still only
requires 3.21. This causes issues when installing the latest PDE in the
Eclipse 4.31, as the JDT bundles are not updated, which therefore leads
to a NoSuchMethodError.

See https://github.com/eclipse-windowbuilder/windowbuilder/issues/865
for a real-life example of this problem.

Amends 00c9caf09d4a5f5be92cbb3e628ef64fa73440f6