Tests: never use System.err

Always print stack traces to System.out, and replace all
System.err.println()'s with System.out.println().

Follow-up of https://android-review.googlesource.com/#/c/187020/ and
https://android-review.googlesource.com/#/c/407032/.

Test: m test-art-host
      m test-art-target
Change-Id: I9ab9cd955a8db25b2ec6673790e5bc924f62c88a
diff --git a/test/146-bad-interface/src/Main.java b/test/146-bad-interface/src/Main.java
index 5534bb4..958ec7c 100644
--- a/test/146-bad-interface/src/Main.java
+++ b/test/146-bad-interface/src/Main.java
@@ -37,7 +37,7 @@
     } catch (Throwable t) {
       System.out.println("Error occurred");
       System.out.println(t);
-      t.printStackTrace();
+      t.printStackTrace(System.out);
     }
   }
 }