Bp2Build for libs property in java_library

Bp2build for both *->java_library and java_library->* edges.

Change-Id: I2540c9af2ae2fe7677767d507647b1c6669b9bb7
Bug: 244210934
Test: ./bp2build testcase, manually inspected build files for hamcrest-library, hamcrest targets
diff --git a/bp2build/testing.go b/bp2build/testing.go
index 0f1a8b2..4e63d19 100644
--- a/bp2build/testing.go
+++ b/bp2build/testing.go
@@ -532,3 +532,10 @@
 	}
 	return MakeBazelTarget("cc_stub_suite", name+"_stub_libs", stubSuiteAttrs)
 }
+
+func MakeNeverlinkDuplicateTarget(moduleType string, name string) string {
+	return MakeBazelTarget(moduleType, name+"-neverlink", AttrNameToString{
+		"neverlink": `True`,
+		"exports":   `[":` + name + `"]`,
+	})
+}