Remove %OS by %TARGET, as spotted by Gareth

tests/test/tblock8.pp

@@ -1,5 +1,5 @@
 { %FAIL }
-{ %OS=darwin,iphonesim,ios}
+{ %TARGET=darwin,iphonesim,ios}
 
 program tblock8;
 

tests/test/tblock9.pp

@@ -1,5 +1,5 @@
 { %FAIL }
-{ %OS=darwin,iphonesim,ios}
+{ %TARGET=darwin,iphonesim,ios}
 
 program tblock9;