1. Rename various shorthand variables
2. Split simple tests into separate Google Test cases (have not tackled
the more complex tests which have loops and/or setup)
3. Remove redundant logging from simple tests
Relates-to: #15913
Consolidate test frameworks and cleanup, including:
* all tests use Google Test
* reorganize folders, esp. kmnkbd -> api
* move all api tests into api folder
* replace references to test_assert or test_color with gtest equivalents
* leverage gtest patterns to remove boilerplate code
* dramatically simplify meson.build files and localize variables
* move shared helper code into helpers/ folder
* make test names unique and add gtest protocol for reporting back to
teamcity
Fixes:
* CLDR test keyboards had invalid unicodeset escapes (needs to be raised
upstream also) - was not failing tests because files were not loading
but returning success
Test-bot: skip
