tui: Output test render to a file for inspection. am: bb248049d1 am: 7a39f7773d am: 47184e31a7 Original change: https://android-review.googlesource.com/c/platform/system/teeui/+/2332344 Change-Id: I01cbd2f40527abd3dbdb52e1906ee1342305fb47 Signed-off-by: Automerger Merge Worker <[email protected]>