REGTESTS: switch to -Ws for master-worker reg-tests

The -W mode implemented in VTest is not reliable anymore, because VTest
waits for the pidfile to be created. But with the new master-worker
mode, this file is created long before haproxy is ready. This can lead
to the test being started too soon, and failing from time to time.

The -Ws option allows to wait for haproxy to deliver a message to VTest
once it is ready.

reg-tests/connection/http_reuse_always.vtc

@@ -2,7 +2,7 @@ varnishtest "Test the http-reuse always mode"
 
 feature ignore_unknown_macro
 
-haproxy h1 -W -conf {
+haproxy h1 -Ws -conf {
 	defaults
 		timeout client 30s
 		timeout server 30s

reg-tests/http-rules/acl_cli_spaces.vtc

@@ -7,7 +7,7 @@ server s1 {
    txresp
 } -repeat 2 -start
 
-haproxy h1 -W -S -conf {
+haproxy h1 -Ws -S -conf {
   defaults
     mode http
     timeout connect "${HAPROXY_TEST_TIMEOUT-5s}"

reg-tests/mcli/mcli_debug_dev.vtc

@@ -19,7 +19,7 @@ syslog S1 -level info {
 } -start
 
 
-haproxy h1 -W -S -conf {
+haproxy h1 -Ws -S -conf {
     global
 	log ${S1_addr}:${S1_port} local0 info
 

reg-tests/mcli/mcli_show_info.vtc

@@ -6,7 +6,7 @@ feature ignore_unknown_macro
 server s1 {
 } -start
 
-haproxy h1 -W -S -conf {
+haproxy h1 -Ws -S -conf {
     defaults
         mode http
         timeout connect "${HAPROXY_TEST_TIMEOUT-5s}"

reg-tests/mcli/mcli_start_progs.vtc

@@ -8,7 +8,7 @@ feature ignore_unknown_macro
 server s1 {
 } -start
 
-haproxy h1 -W -S -conf {
+haproxy h1 -Ws -S -conf {
     global
         expose-deprecated-directives
     defaults

reg-tests/seamless-reload/abns_socket.vtc

@@ -23,7 +23,7 @@ feature cmd "command -v grep"
 #EXCLUDE_TARGETS=freebsd,osx,generic
 #REGTEST_TYPE=devel
 
-haproxy h1 -W -S -conf {
+haproxy h1 -Ws -S -conf {
   global
     stats socket "${tmpdir}/h1/stats" level admin expose-fd listeners
 

reg-tests/server/abnsz.vtc

@@ -6,7 +6,7 @@ feature cmd "command -v curl"
 #EXCLUDE_TARGETS=freebsd,osx,generic
 #REGTEST_TYPE=devel
 
-haproxy h1 -W -S -conf {
+haproxy h1 -Ws -S -conf {
   global
     stats socket "${tmpdir}/h1/stats" level admin expose-fd listeners