CI: drop asan.log umbrella completely

asan.log redirection appeared to work poorly, let's cease that practice
for good.

ML: https://www.mail-archive.com/haproxy@formilux.org/msg44844.html

.github/workflows/vtest.yml

@@ -141,9 +141,6 @@ jobs:
       run: echo "::add-matcher::.github/vtest.json"
     - name: Run VTest for HAProxy ${{ steps.show-version.outputs.version }}
       id: vtest
-      env:
-        # Force ASAN output into asan.log to make the output more readable.
-        ASAN_OPTIONS: log_path=asan.log
       run: |
         # This is required for macOS which does not actually allow to increase
         # the '-n' soft limit to the hard limit, thus failing to run.
@@ -167,12 +164,6 @@ jobs:
           cat $folder/LOG
           echo "::endgroup::"
         done
-        shopt -s nullglob
-        for asan in asan.log*; do
-          echo "::group::$asan"
-          cat $asan
-          echo "::endgroup::"
-        done
         exit 1
 
     - name: Show coredumps