Update truth-prebuilt to 0.44.

This is a transitional step on the road to truth-1.0.1. A lot of the new
APIs were added in truth 0.44 without the old ones being deleted yet,
making incremental migration possible.

Bug: 168765701
Test: m checkbuild
Change-Id: Icf7c9944895e4d30de51e2d9d67b0ed23e842e17