* fixture.h: added TODO
* TestPlatform: improved tests for built-in platforms
* TestPlatform: changed tests to TODO asserts
* testfilelister.cpp: added TODO
* fixture.h: added `PLATFORM` macro to load platform / use `PLATFORM` in tests
* platform.h: corrected capitalization in `Platform::platformString(PlatformType)` and bail on unknown type
* fixture.h: fixed `readability-redundant-string-cstr` clang-tidy warning
* testplatform.cpp: fixed `functionConst` selfcheck warnings
Oliver Stöneberg
Daniel Marjamäki