java/syncbase: Fix remaining core and internal tests

It looks like some of these tests weren't quite right, so here are
the remaining fixes.

./gradlew test should work
and with v.io/c/23856, we should be able to run them with jiri soon.

Change-Id: Ifd78654ffc8bc9f5d3e509d0e351ce18c36b4584
4 files changed