Enable coverage for core-oj.

For now, only a whitelisted set of packages are whitelisted (see
libcore/JavaLibrary.bp) but this works as a proof-of-concept.

Bug: 64836607
Test: `cts-tradefed run cts-dev -m CtsLibcoreTestCases --test-arg com.android.compatibility.testtype.LibcoreTest:coverage:true` on a build with EMMA_INSTRUMENT=true and EMMA_INSTRUMENT_FRAMEWORK=true
Change-Id: If7c62665257f0ff9466030680ff1f56a053a023e

java/config/config.go

@@ -39,6 +39,7 @@ var (
 		"services",
 		"android.car",
 		"android.car7",
+		"core-oj",
 	}
 )