Fix or suppress some google-runtime-int warnings.

* Use time_t for tv_sec type.
* Use 'auto' to avoid explicitly use of 'long'.
* Use (u)int16_t instead of (unsigned) short.

Bug: 112478838
Test: build with WITH_TIDY=1
Change-Id: I023e579b071688731064e51dc94f404274cd59e2