remove kA1_Config, as it is no longer supported

BUG=
R=djsollen@google.com

Review URL: https://codereview.chromium.org/83093005

git-svn-id: http://skia.googlecode.com/svn/trunk@12384 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/ImageDecodingTest.cpp b/tests/ImageDecodingTest.cpp
index 56193f4..6fcef1d 100644
--- a/tests/ImageDecodingTest.cpp
+++ b/tests/ImageDecodingTest.cpp
@@ -148,7 +148,7 @@
         // the list is that each one is different, so we can test
         // to make sure the correct config is chosen.
         const SkBitmap::Config configs[] = {
-            SkBitmap::kA1_Config,
+            SkBitmap::kA8_Config,
             SkBitmap::kA8_Config,
             SkBitmap::kIndex8_Config,
             SkBitmap::kRGB_565_Config,