hidl_test_java interfaces: use generic interfaces

In places where we are passing interfaces, pass around
android.hidl.base.IBase to give flexibility to the test implementation,
specifically in order to avoid passing local binders to Java process,
which is a disabled feature.

Bug: 169369810
Test: atest hidl_test hidl_test_java
Change-Id: I7721a6ec7e72b96915a0dc66aa8e75c327032d1f