Print backtrace of microdroid_manager to kmsg

To track any possible bugs on microdroid_manager.

Bug: 258760809
Test: intentionally crash microdroid_manager and see console
Change-Id: I2359e59270a1c6c5efab2a6cb1e0727bb3c5743e
diff --git a/microdroid_manager/microdroid_manager.rc b/microdroid_manager/microdroid_manager.rc
index cfa70bd..c41ee38 100644
--- a/microdroid_manager/microdroid_manager.rc
+++ b/microdroid_manager/microdroid_manager.rc
@@ -1,6 +1,9 @@
 service microdroid_manager /system/bin/microdroid_manager
     disabled
+    # print android log to kmsg
     file /dev/kmsg w
+    # redirect stdout/stderr to kmsg_debug
+    stdio_to_kmsg
     setenv RUST_LOG info
     # TODO(jooyung) remove this when microdroid_manager becomes a daemon
     oneshot