[clang-tidy]: Abseil: new check 'abseil-upgrade-duration-conversions'
Patch by Alex Strelnikov.
Reviewed as D53830
Introduce a new check to upgrade user code based on upcoming API breaking changes to absl::Duration.
The check finds calls to arithmetic operators and factory functions for absl::Duration that rely on
an implicit user defined conversion to int64_t. These cases will no longer compile after proposed
changes are released. Suggested fixes explicitly cast the argument int64_t.