Avoid drawing NVPR DIF text when text size is 0

Avoid drawing text when using NVPR and device independent fonts.
The drawing calculations cause division by zero and produce NaNs
to transforms (due to fTextInverseRatio).

Reproed by top25desk_twitter.skp as well as the added testcase.
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1760163002

Review URL: https://codereview.chromium.org/1760163002
4 files changed