Enable real test discovery in build_test_suites

Enable test discovery to actually affect build targets in build_test_suites.py (only when the flags are enabled. On failure of test discovery or if the flags are off instead fall back to the previous optimizations.

Change-Id: I6937dd0c5096884095d0770bc53b6399233cefc2
Test: atest build_test_suites_test
Bug: 378926009
diff --git a/ci/build_test_suites_test.py b/ci/build_test_suites_test.py
index 503a5f4..29d268e 100644
--- a/ci/build_test_suites_test.py
+++ b/ci/build_test_suites_test.py
@@ -120,6 +120,9 @@
     self.soong_ui_dir = self.fake_top.joinpath('build/soong')
     self.soong_ui_dir.mkdir(parents=True, exist_ok=True)
 
+    self.logs_dir = self.fake_top.joinpath('dist/logs')
+    self.logs_dir.mkdir(parents=True, exist_ok=True)
+
     self.soong_ui = self.soong_ui_dir.joinpath('soong_ui.bash')
     self.soong_ui.touch()