coveralls.yml: Avoid excluding subdirectories of already excluded dirs

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Saša Nedvědický <sashan@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/26405)

.github/workflows/coveralls.yml

@@ -80,8 +80,6 @@ jobs:
     - name: generate coverage info
       run: lcov -d . -c
              --exclude "${PWD}/test/*"
-             --exclude "${PWD}/test/helpers/*"
-             --exclude "${PWD}/test/testutil/*"
              --exclude "${PWD}/fuzz/*"
              --exclude "/usr/include/*"
              --ignore-errors mismatch