Bug 440354 - [jobs] Don't call belongsTo with null in JobManager#join

Implementations may not expect a null family.

Signed-off-by: Robin Stocker <robin@nibor.org>
Bug 432079 - Clean up org.eclipse.core.jobs

Generics and un-necessery casts cleanup in
eclipse.platform.runtime/tests

Change-Id: Ia10647eb3f75fdde48bcc91e8e7ab74d720cc3ef
Signed-off-by: Thirumala Reddy Mutchukota <thirumala@google.com>