Change #ifdef's for ENABLE_GLOBAL_IMAGE_CACHE_FOR_SVGKIMAGE_IMAGE_NAMED to work as expected.

The expected behaviour is that the #if'd code will compile only when
ENABLE_GLOBAL_IMAGE_CACHE_FOR_SVGKIMAGE_IMAGE_NAMED is set to 1. Thus,
to make the code compile as expected all the #ifdefs were changed to #ifs.