add avx2 wrappers for functions that can call I422ToARGBRow_AVX2

libyuv.gyp

Index: libyuv.gyp
diff --git a/libyuv.gyp b/libyuv.gyp
index 44dec09eeca01f6864a6fe100644ec80f2ccacce..cd4db1abab903a657a47b0ab8ab6906c3c9bc424 100644
--- a/libyuv.gyp
+++ b/libyuv.gyp
@@ -42,7 +42,7 @@
       # Change type to 'shared_library' to build .so or .dll files.
       'type': 'static_library',
       'variables': {
-        'optimize': 'max',  # enable O2 and ltcg.
+        # 'optimize': 'max',  # enable O2 and ltcg.
       },
       # Allows libyuv.a redistributable library without external dependencies.
       'standalone_static_library': 1,