Increase gcloop threshold to 15

12 seems to be flaky for the JIT configuration.

Bug: 35917229

Test: test-art-host

Change-Id: Ia3bcd542d58f1dce16d2bc21cbee9f5d2650035f
diff --git a/test/154-gc-loop/src/Main.java b/test/154-gc-loop/src/Main.java
index 2228ca2..69015b6 100644
--- a/test/154-gc-loop/src/Main.java
+++ b/test/154-gc-loop/src/Main.java
@@ -38,7 +38,7 @@
         }
     } catch (Exception e) {}
     System.out.println("Finalize count too large: " +
-            ((finalizeCounter >= 12) ? Integer.toString(finalizeCounter) : "false"));
+            ((finalizeCounter >= 15) ? Integer.toString(finalizeCounter) : "false"));
   }
 
   private static native void backgroundProcessState();