Disable RAW test when SkRawCodec is not compiled

TBR=scroggo@google.com

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1639533002

Review URL: https://codereview.chromium.org/1639533002
diff --git a/tests/CodexTest.cpp b/tests/CodexTest.cpp
index 11d02cd..b6b5d82 100644
--- a/tests/CodexTest.cpp
+++ b/tests/CodexTest.cpp
@@ -649,7 +649,9 @@
     test_dimensions(r, "mandrill_16.png");
 
     // RAW
+#if defined(SK_CODEC_DECODES_RAW)
     test_dimensions(r, "sample_1mp.dng");
+#endif
 }
 
 static void test_invalid(skiatest::Reporter* r, const char path[]) {