When rendering, wait for the RenderThread to be done

With layoutlib using an actual RenderThread, the rendering method needs
to wait for the render thread to have finished its job before setting
the render image data.

Flag: NONE host-only change
Bug: 74062470
Test: layoutlib tests
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:1d954e44f62fa87a71ea87f3fbe9da7c61e25482)
Merged-In: I9f3fb731ec06d44d567f6ebfdb9229066b2f1048
Change-Id: I9f3fb731ec06d44d567f6ebfdb9229066b2f1048