Utility: make FileWatcherTest not XPASS on iOS.

This used to fail on iOS back when Travis CI was used, but on CircleCI
emulator it passes. Since the whole thing needs to be reworked to use OS
filesystem watchers (and it's quite useless on iOS anyway), I don't
really care.

Author: mosra

src/Corrade/Utility/Test/FileWatcherTest.cpp

@@ -322,9 +322,10 @@ void FileWatcherTest::changedClearedIgnoreEmpty() {
     /* When the file becomes non-empty again, the change is signalled */
     CORRADE_VERIFY(Directory::writeString(_filename, "some content again"));
     {
-        #ifdef CORRADE_TARGET_IOS
-        CORRADE_EXPECT_FAIL("iOS seems to be reporting all file sizes to be 0, so the IgnoreChangeIfEmpty flag is ignored there.");
-        #endif
+        /* This used to fail on iOS back when Travis CI was used, but on
+           CircleCI emulator it passes. Since the whole thing needs to be
+           reworked to use OS filesystem watchers (and it's quite useless on
+           iOS anyway), I don't really care. */
         CORRADE_VERIFY(watcher.hasChanged());
     }
 }