Add test coverage for bitmap font rendering using the Spleen 8x16 font
in three formats: BDF (Bitmap Distribution Format), PCF (Portable
Compiled Format), and OTB (OpenType Bitmap). Tests validate glyph
rendering against expected pixel patterns.
Addresses #8524.
Rather than using binaries statically in our source tree; this makes
them easier to update. This also makes it so that they are separated
from each other rather than using a patched JB mono as our fallback.
Fixes#2364
This adds the bold, italic, and bold italic variants of JB Mono so it is
built-in. This also fixes up the naming convention for the embedded font
files across tests and removes redundant embedded font files.