[clang-tidy] Move part of bugprone-unhandled-code-paths to a new check readability-trivial-switch (#198237)
The moved part detects trivial `switch` statement which can be removed
or rewritted as `if` statement.
hicpp-multiway-paths-covered was removed without keeping its name as
alias, so we don't need to update infrastructore to support one-to-many
aliases.
Changes were generated by AI, and reviewed and modified by me
afterwards.
Assisted-by: GPT-5.5