A java_test with multiple files should provide symbols to itself

[cgrushko]

For example,
A depends on B, and both are in a java_test.
Currently, Jadep will not find a satisfying rule for B, even though the java_test provides B and there's no need for another dependency.

The same scenario works for java_library, and the reason is that java_test's are not considered because they're not rules a Java rule can deps on.