Use newline to separate stack trace lines

It was unintentionally removed in patchset 3 of ag/3221176

Test: manual
Change-Id: Iede0bfe1b5d622fda794ddf4a0bcdbdaeeb4939d
diff --git a/core/java/android/os/Parcel.java b/core/java/android/os/Parcel.java
index d092018..36121d4 100644
--- a/core/java/android/os/Parcel.java
+++ b/core/java/android/os/Parcel.java
@@ -1780,7 +1780,7 @@
             final int truncatedSize = Math.min(stackTrace.length, 5);
             StringBuilder sb = new StringBuilder();
             for (int i = 0; i < truncatedSize; i++) {
-                sb.append("\tat ").append(stackTrace[i]);
+                sb.append("\tat ").append(stackTrace[i]).append('\n');
             }
             writeString(sb.toString());
             final int payloadPosition = dataPosition();