java: Add a minimal test for the Syncbase internal API

This is an Android instrumented unit test. Running it currently
results in a Go stracktrace but it does confirm that the loading of
the .so takes place as expected.

The 'multiDexEnabled true' added to the build.gradle is necessary
because the number of functions goes over 64K.

Change-Id: I2b27920f1f44449b5411355d6d9515ea0be5c64b
2 files changed