Atest: speed up searching when null args.tests

When running atest without test references, the amount of tests could be
extremely huge and result in very inefficient fuzzy searching process.

BUG: 184889747

Test: lunch slider-userdebug
croot vendor/google/services/LyricCameraHAL/src
atest-dev -v --host --dry-run

Change-Id: I3f6ef5210506685489185027022148bf0407af31
Merged-In: Ia77a4aac54bc9126b44ceafa9683c4298935a30f
Merged-In: I808dc0f273e65b35d3482a5932aa4ae259195c9f
4 files changed