Previously disambiguation was looking for exact matches,
but vector buses are permitted to have different ranges and
still participate in merging, so they need to be disambiguated.
Fixes https://gitlab.com/kicad/code/kicad/-/issues/5925
This moves the program-specific code (e.g. BIU files) into
the program tests.
Also, create title_block.cpp to break a dependency that pulled
in eda_text.cpp when using the TITLE_BLOCK object.