Access output files thru providers in Soong tests.

The outputFiles field on ModuleBase will be removed next.

Bug: 358425833
Test: CI
Change-Id: I6d665ac13134d9278e5908f64c454366bc6bca5e
diff --git a/java/app_test.go b/java/app_test.go
index 6b7d522..ec97a55 100644
--- a/java/app_test.go
+++ b/java/app_test.go
@@ -119,7 +119,7 @@
 		foo.Output(expectedOutput)
 	}
 
-	outputFiles := foo.OutputFiles(t, "")
+	outputFiles := foo.OutputFiles(ctx, t, "")
 	android.AssertPathsRelativeToTopEquals(t, `OutputFiles("")`, expectedOutputs, outputFiles)
 }