map list files must have newline characters

module_names.txt and module_paths.txt did not end with the newline
character in each line. Instead it had literal '\n'.
The character must use '\n' without escape character.

Test: m vndk
Change-Id: I1de1d0993994c8a95b02426777f62bfb2bed7b6f
diff --git a/cc/vndk.go b/cc/vndk.go
index 4a005f3..fcaf3af 100644
--- a/cc/vndk.go
+++ b/cc/vndk.go
@@ -727,7 +727,7 @@
 		var txtBuilder strings.Builder
 		for idx, k := range android.SortedStringKeys(m) {
 			if idx > 0 {
-				txtBuilder.WriteString("\\n")
+				txtBuilder.WriteString("\n")
 			}
 			txtBuilder.WriteString(k)
 			txtBuilder.WriteString(" ")