Fix the css parser value inherit test

This was affected by the recent renaming of icon-shadow to
-gtk-icon-shadow. Also, it produces an error now because
engine is deprecated.

testsuite/css/parser/Makefile.am

@@ -403,6 +403,7 @@ test_data = \
 	transition.css \
 	transition.ref.css \
 	value-inherit.css \
+	value-inherit.errors \
 	value-inherit-shorthand.css \
 	value-inherit-shorthand.ref.css \
 	value-initial.css \

testsuite/css/parser/value-inherit.css

@@ -1,4 +1,5 @@
 * {
+  -gtk-icon-shadow: inherit;
   background-clip: inherit;
   background-color: inherit;
   background-image: inherit;
@@ -33,7 +34,6 @@
   font-style: inherit;
   font-variant: inherit;
   font-weight: inherit;
-  icon-shadow: inherit;
   margin-bottom: inherit;
   margin-left: inherit;
   margin-right: inherit;

testsuite/css/parser/value-inherit.errors

@@ -0,0 +1 @@
+value-inherit.css:30: error: GTK_CSS_PROVIDER_ERROR_DEPRECATED