Fix race between System.out.println & System.err.println in 087-gc-after-link

Always print to System.out to avoid out-of-expected-order outputs.

Test: art/test/testrunner/testrunner.py -t 087-gc-after-link
Change-Id: Ic36baa9ef1bf4edb9265872e58b2a6e85a424c3f
diff --git a/test/087-gc-after-link/src/Main.java b/test/087-gc-after-link/src/Main.java
index 698af0b..6f686fd 100644
--- a/test/087-gc-after-link/src/Main.java
+++ b/test/087-gc-after-link/src/Main.java
@@ -165,14 +165,14 @@
 
             loader = new BrokenDexLoader(ClassLoader.getSystemClassLoader());
             loader.findBrokenClass();
-            System.err.println("ERROR: Inaccessible was accessible");
+            System.out.println("ERROR: Inaccessible was accessible");
         } catch (InvocationTargetException ite) {
             Throwable cause = ite.getCause();
             if (cause instanceof NullPointerException) {
-                System.err.println("Got expected ITE/NPE");
+                System.out.println("Got expected ITE/NPE");
             } else {
-                System.err.println("Got unexpected ITE");
-                ite.printStackTrace();
+                System.out.println("Got unexpected ITE");
+                ite.printStackTrace(System.out);
             }
         }
     }