Deflake ChoreographerTest:InputCallbackBeforeAnimation

When requesting a callback allow more time than a single
vsync to recieve the callbacks before testing the callback
order. Also clean up the test to remove redundant callback
and make the error conditions easier to read.

Flag: EXEMPT test fix
Fixes: 365708032
Test: atest libgui_test:ChoreographerTest --rerun-until-failure
Change-Id: I3fef7cc14880d5414109760308668a0a848271c4