flags and hacks to get MSAN bot going

src/images/SkImageDecoder_libjpeg.cpp

Index: src/images/SkImageDecoder_libjpeg.cpp
diff --git a/src/images/SkImageDecoder_libjpeg.cpp b/src/images/SkImageDecoder_libjpeg.cpp
index 6a3ae87b6a113da85e3291d7a91e3526ffde5140..89bfefcd45f2ae68b98a7d6030fbac7f9a7f0eef 100644
--- a/src/images/SkImageDecoder_libjpeg.cpp
+++ b/src/images/SkImageDecoder_libjpeg.cpp
@@ -509,6 +509,8 @@ SkImageDecoder::Result SkJPEGImageDecoder::onDecode(SkStream* stream, SkBitmap*
     for (int y = 0;; y++) {
         JSAMPLE* rowptr = (JSAMPLE*)srcRow;
         int row_count = jpeg_read_scanlines(&cinfo, &rowptr, 1);
+        sk_msan_mark_initialized(srcRow, srcRow + cinfo.output_width * srcBytesPerPixel,
+                                 "skbug.com/4550");
         if (0 == row_count) {
             // if row_count == 0, then we didn't get a scanline,
             // so return early.  We will return a partial image.
@@ -525,8 +527,6 @@ SkImageDecoder::Result SkJPEGImageDecoder::onDecode(SkStream* stream, SkBitmap*
             convert_CMYK_to_RGB(srcRow, cinfo.output_width);
         }
 
-        sk_msan_mark_initialized(srcRow, srcRow + cinfo.output_width * srcBytesPerPixel,
-                                 "skbug.com/4550");
 
         sampler.next(srcRow);
         if (bm->height() - 1 == y) {