CI: Github Actions: do not show VTest failures if build failed

this is mostly cleanup, issue is minor. If build failed, VTest execution
tried to be performed as well as VTest result show. This change ignores
those steps if build failed.

.github/workflows/vtest.yml

@@ -87,6 +87,7 @@ jobs:
           ADDLIB="-Wl,-rpath,/usr/local/lib/ -Wl,-rpath,$HOME/opt/lib/"
         sudo make install
     - name: Show HAProxy version
+      if: ${{ !failure() }}
       id: show-version
       run: |
         echo "::group::Show dynamic libraries."
@@ -101,17 +102,19 @@ jobs:
         haproxy -vv
         echo "::set-output name=version::$(haproxy -v |awk 'NR==1{print $3}')"
     - name: Install problem matcher for VTest
+      if: ${{ !failure() }}
       # This allows one to more easily see which tests fail.
       run: echo "::add-matcher::.github/vtest.json"
     - name: Run VTest for HAProxy ${{ steps.show-version.outputs.version }}
+      if: ${{ !failure() }}
       id: vtest
       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.
         ulimit -n 5000
         make reg-tests VTEST_PROGRAM=../vtest/vtest REGTESTS_TYPES=default,bug,devel
-    - name: Show results
-      if: ${{ failure() }}
+    - name: Show VTest results
+      if: ${{ failure() && steps.vtest.outcome == 'failure' }}
       run: |
         for folder in ${TMPDIR}/haregtests-*/vtc.*; do
           printf "::group::"