Disable color space test for old versions of libpng

Should fix the Google3 build.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1769953002

Review URL: https://codereview.chromium.org/1769953002
1 file changed