In commit b2c14bc774 (cmake -E: Add cmake_transform_depfile internal
command, 2020-10-02, v3.20.0-rc1~684^2~2) a partial implementation for
converting MSBuild "TLog" format files was added. However, it is
unused and incomplete:
* Does not enforce absolute paths as TLog docs require.
* Does not upper-case paths as TLog docs recommend.
* The TLog format semantics are not equivalent to `out: in`.
Remove the unused TLog transform infrastructure to avoid confusion.
Issue: #20286