REGTESTS: use -dI for insecure fork by default in the regtest scripts

Let's remove the CI HAPROXY_ARGS setting and set -dI for anything run
with the run-regtests.sh.

.github/workflows/vtest.yml

@@ -149,7 +149,7 @@ jobs:
         # the '-n' soft limit to the hard limit, thus failing to run.
         ulimit -n 65536
         ulimit -c unlimited
-        make reg-tests HAPROXY_ARGS="-dI" VTEST_PROGRAM=../vtest/vtest REGTESTS_TYPES=default,bug,devel
+        make reg-tests VTEST_PROGRAM=../vtest/vtest REGTESTS_TYPES=default,bug,devel
     - name: Config syntax check memleak smoke testing
       if: ${{ contains(matrix.name, 'ASAN') }}
       run: |

scripts/run-regtests.sh

@@ -312,7 +312,7 @@ _version() {
 
 
 HAPROXY_PROGRAM="${HAPROXY_PROGRAM:-${PWD}/haproxy}"
-HAPROXY_ARGS="${HAPROXY_ARGS--dM}"
+HAPROXY_ARGS="${HAPROXY_ARGS--dM -dI}"
 VTEST_PROGRAM="${VTEST_PROGRAM:-vtest}"
 TESTDIR="${TMPDIR:-/tmp}"
 REGTESTS=""