Logging the stack trace for system anomaly messages

With these system anomalies, you are never sure that the system/tests will be able to normally bubble up the error.

Bug: 203416429
Test: presubmit

Change-Id: Ie1d3d183cf6e56778d5c052ef7b8e0541bbc6255
(cherry picked from commit 37542c8c0e1aed42fcdbd8406f0257cd5fea48bf)
diff --git a/tests/tapl/com/android/launcher3/tapl/LauncherInstrumentation.java b/tests/tapl/com/android/launcher3/tapl/LauncherInstrumentation.java
index 2fbe460..3485dd1 100644
--- a/tests/tapl/com/android/launcher3/tapl/LauncherInstrumentation.java
+++ b/tests/tapl/com/android/launcher3/tapl/LauncherInstrumentation.java
@@ -544,11 +544,11 @@
                     : TestHelpers.getSystemHealthMessage(getContext(), mTestStartTime);
 
             if (systemHealth != null) {
-                return message
-                        + ";\nPerhaps linked to system health problems:\n<<<<<<<<<<<<<<<<<<\n"
+                message += ";\nPerhaps linked to system health problems:\n<<<<<<<<<<<<<<<<<<\n"
                         + systemHealth + "\n>>>>>>>>>>>>>>>>>>";
             }
         }
+        Log.d(TAG, "About to throw the error: " + message, new Exception());
         return message;
     }