vboot/ui: Split out screen tests

Split out screen tests with individual test items.

Add three macros which record line numbers:
DISPLAYED_EQ, DISPLAYED_PASS, and DISPLAYED_NO_EXTRA.

BUG=b:146399181, b:156448738
TEST=CC=x86_64-pc-linux-gnu-clang;
     make clean && make runtests
TEST=CC=x86_64-pc-linux-gnu-clang; DETACHABLE=1;
     make clean && make runtests
TEST=CC=x86_64-pc-linux-gnu-clang; PHYSICAL_PRESENCE_KEYBOARD=1;
     make clean && make runtests
BRANCH=none

Signed-off-by: Hsuan Ting Chen <roccochen@chromium.org>
Change-Id: I712e009658fecad66553423c2d05e8e7c9df7e08
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2228254
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
2 files changed