CTS Holo: Enlarge the threshold from 1 to 2

Optimized Skia implementation may have 1 bit difference with the accurate result,
which is same as Google's default Skia implementation.
But other vendor may choose different optimization with Google's,
so the maximum difference between Google's C optimization and other vendor's optimization may be 2

Change-Id: Iac19e6b8bd53b3932ebb38c12c4b795ee31316f8
Signed-off-by: Xu Ziyi <zyxu@marvell.com>
diff --git a/tests/tests/holo/src/android/holo/cts/LayoutTestActivity.java b/tests/tests/holo/src/android/holo/cts/LayoutTestActivity.java
index 24c8088..2d56dad 100755
--- a/tests/tests/holo/src/android/holo/cts/LayoutTestActivity.java
+++ b/tests/tests/holo/src/android/holo/cts/LayoutTestActivity.java
@@ -163,7 +163,7 @@
         protected void onPreExecute() {
             mBitmap = getBitmap();
             mReferenceBitmap = BitmapAssets.getBitmap(getApplicationContext(), mBitmapName);
-            final int threshold = 1;
+            final int threshold = 2;
             mSame = compareTo(mBitmap, mReferenceBitmap, threshold);
         }