Fix wrong type in host version of ThreadBase

Do not use int for the timeout as it risks overflowing, leading to wrong
computations of wait times for the render thread queue in the host
version of libhwui.

Flag: NONE host-only change
Bug: 367381897
Test: checked on host
Change-Id: Ie5119c72b5f34bf481bfda3dae334c756c8acae5