GStreamer text rendering on Windows breaks some text in HLFF/HF

[shippy]

In the course of fixing #124, I came across this weird thing. In the high-fat condition (but not the low-fat condition) of HLFF, the loss text label and the reference text label are slightly broken.

In the image above, look at the slightly jumping baseline of the top text, as well as the partial crop that's going on. By contrast, using almost the same setup but substituting low-fat config for the high-fat config, we get correct rendering:

In the preliminary testing, this does not seem to be specific to the word "Oreos" — any word with that config breaks in that position.

(This is potentially related to what @ruonan-jia has been seeing on her workstation.)

The diagnostics/debugging should include:

• look closely at the differences between the HF and the LF configuration
• try this on a different Windows machine with GStreamer installed (preferably with and without 2 monitors)
• try this on a Mac