vboot/ui: Split UI tests

Rearrange UI tests into three files: vb2_ui_utility_tests for utility
functions and core UI functions, vb2_ui_action_tests for hooked actions,
and vb2_ui_tests for UI entries.

This CL does not add any extra tests.

TEST=make clean && make runtests
TEST=make clean && DETACHABLE=1; make runtests

Signed-off-by: Hsuan Ting Chen <roccochen@chromium.org>
Change-Id: I36a0a43aa3295b06cf32446dcc107652d64d2b8f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/2198268
Reviewed-by: Joel Kitching <kitching@chromium.org>
4 files changed