Bp2build Java libs for java_binary -> java_import edge

Since Bazel's java_import requires a jars attribute to be specified,
the generated neverlink-duplicated module is of type java_library

Change-Id: I14a866dfc583507a9462add50d95060cbfe540c5
Bug: 244210934
Test: m bp2build, go test ./bp2build, manual inspection of generated Build and jar files