[ci,cov] Clean up output directories before collecting coverage data

This ensures that the output directories are empty before we start
collecting data, avoiding potential issues with stale data from previous
runs.

Change-Id: I8eaba03e802c1703183fc8c93e0f7c1d5e6463f4
Signed-off-by: Yi-Hsuan Deng <yhdeng@google.com>

Author: sasdf

ci/scripts/collect-coverage-report.sh

@@ -26,13 +26,15 @@ cp -r bazel-out/_coverage/* "${OUTPUT_DIR}" || true
 find "${OUTPUT_DIR}" -type f -exec chmod 644 {} +
 
 echo "Collect all test coverage data"
+rm -rf "${TESTS:?}"
 mkdir -p "${TESTS}"
 rsync -a --ignore-missing-args --files-from="${LCOV_FILES}" . "${TESTS}/"
 
 echo "Merge all coverage data"
 find "${TESTS}" -type f -name "*.dat" -exec cat {} + > "${COVERAGE}"
 
 echo "Collect all test logs"
+rm -rf "${LOGS:?}"
 mkdir -p "${LOGS}"
 cat "${LCOV_FILES}" | while read -r lcov; do
   test_dir=$(dirname "${lcov}")
@@ -44,6 +46,7 @@ cat "${LCOV_FILES}" | while read -r lcov; do
 done
 
 echo "Collect all source files listed in coverage data"
+rm -rf "${SOURCES:?}"
 mkdir -p "${SOURCES}"
 grep -h '^SF:' "${COVERAGE}" | sed 's/^SF://' | sort -u > "${SOURCE_LIST}"
 python3 util/fetch-remote-cache.py --file-list="${SOURCE_LIST}"