Properly log in build_test_suites.py

Set up logging properly in build_test_suites.py so that the log file is
directed to the dist dir (and /tmp if it is not defined)

Test: atest build_test_suites_test
Bug: 355074139
Change-Id: I16ce644f1c717179377c8ca68c74d9af5f2e61df

ci/build_test_suites.py

@@ -28,6 +28,7 @@ import optimized_targets
 
 REQUIRED_ENV_VARS = frozenset(['TARGET_PRODUCT', 'TARGET_RELEASE', 'TOP'])
 SOONG_UI_EXE_REL_PATH = 'build/soong/soong_ui.bash'
+LOG_PATH = 'logs/build_test_suites.log'
 
 
 class Error(Exception):
@@ -181,4 +182,12 @@ def run_command(args: list[str], stdout=None):
 
 
 def main(argv):
+  dist_dir = os.environ.get('DIST_DIR')
+  if dist_dir:
+    log_file = pathlib.Path(dist_dir) / LOG_PATH
+    logging.basicConfig(
+        level=logging.DEBUG,
+        format='%(asctime)s %(levelname)s %(message)s',
+        filename=log_file,
+    )
   sys.exit(build_test_suites(argv))