Code Coverage: store lcov report (#4358)

## Problem

In the future, we want to compare code coverage on a PR with coverage on
the main branch.
Currently, we store only code coverage HTML reports, I suggest we start
storing reports in "lcov info" format that we can use/parse in the
future. Currently, the file size is ~7Mb (it's a text-based format and
could be compressed into a ~400Kb archive)

- More about "lcov info" format:
https://manpages.ubuntu.com/manpages/jammy/man1/geninfo.1.html#files
- Part of https://github.com/neondatabase/neon/issues/3543

## Summary of changes
- Change `scripts/coverage` to output lcov coverage to
`report/lcov.info` file instead of stdout (we already upload the whole
`report/` directory to S3)

.github/workflows/build_and_test.yml

@@ -492,19 +492,24 @@ jobs:
         env:
           COMMIT_URL: ${{ github.server_url }}/${{ github.repository }}/commit/${{ github.event.pull_request.head.sha || github.sha }}
         run: |
-          scripts/coverage \
-            --dir=/tmp/coverage report \
+          scripts/coverage --dir=/tmp/coverage \
+            report \
             --input-objects=/tmp/coverage/binaries.list \
             --commit-url=${COMMIT_URL} \
             --format=github
 
+          scripts/coverage --dir=/tmp/coverage \
+            report \
+            --input-objects=/tmp/coverage/binaries.list \
+            --format=lcov
+
       - name: Upload coverage report
         id: upload-coverage-report
         env:
           BUCKET: neon-github-public-dev
           COMMIT_SHA: ${{ github.event.pull_request.head.sha || github.sha }}
         run: |
-          aws s3 cp --only-show-errors --recursive /tmp/coverage/report s3://neon-github-public-dev/code-coverage/${COMMIT_SHA}
+          aws s3 cp --only-show-errors --recursive /tmp/coverage/report s3://${BUCKET}/code-coverage/${COMMIT_SHA}
 
           REPORT_URL=https://${BUCKET}.s3.amazonaws.com/code-coverage/${COMMIT_SHA}/index.html
           echo "report-url=${REPORT_URL}" >> $GITHUB_OUTPUT