Fix flakyness in failure_setup (#6205)

In CI sometimes failure_setup will fail with the following error:
```diff
 SELECT master_add_node('localhost', :worker_2_proxy_port);  -- an mitmproxy which forwards to the second worker
- master_add_node
----------------------------------------------------------------------
-               2
-(1 row)
-
+ERROR:  connection to the remote node localhost:9060 failed with the following error: could not connect to server: Connection refused
+	Is the server running on host "localhost" (127.0.0.1) and accepting
+	TCP/IP connections on port 9060?
+could not connect to server: Connection refused
+	Is the server running on host "localhost" (127.0.0.1) and accepting
+	TCP/IP connections on port 9060?
+could not connect to server: Cannot assign requested address
+	Is the server running on host "localhost" (::1) and accepting
+	TCP/IP connections on port 9060?
diff -dU10 -w /home/circleci/project/src/test/regress/expected/failure_online_move_shard_placement.out /home/circleci/project/src/test/regress/results/failure_online_move_shard_placement.out
```

This then breaks all the tests run after it as well, because we're
missing one worker node.

Locally I was able to reproduce this error by sleeping for 10 seconds in
the forked process sleep before actually starting mitmproxy. So I'm
expecting what's happening in CI is that due to limited resources,
mitmproxy is not up yet when we try to add its port as a workernode.

This PR fixes this by waiting until mitmproxy is listening on its socket
before actually starting to run our tests. This fixed it locally for me
when I made the forked process sleep for 10 seconds before starting
mitmproxy.

In passing it also improves the detection and errors that we already
had for the case where something was already listening on the 
mitmproxy port.

Because both @gledis69 and me were changing things in our CI images
at the same time this also includes a bump of the style checker tools.
Closes #6200

.circleci/config.yml

@@ -6,7 +6,7 @@ orbs:
 parameters:
   image_suffix:
     type: string
-    default: '-v0aadde0'
+    default: '-vb4dd087'
   pg13_version:
     type: string
     default: '13.4'
@@ -18,7 +18,7 @@ parameters:
     default: '13.4-14.0-15beta3'
   style_checker_tools_version:
     type: string
-    default: '0.7.9'
+    default: '0.8.18'
 jobs:
   build:
     description: Build the citus extension

src/test/regress/pg_regress_multi.pl

@@ -789,18 +789,17 @@ if ($useMitmproxy)
     die "a file already exists at $mitmFifoPath, delete it before trying again";
   }
 
-  system("lsof -i :$mitmPort");
-  if (! $?) {
-    die "cannot start mitmproxy because a process already exists on port $mitmPort";
-  }
-
   if ($Config{osname} eq "linux")
   {
-    system("netstat --tcp -n | grep $mitmPort");
+    system("netstat --tcp -n | grep :$mitmPort");
   }
   else
   {
-    system("netstat -p tcp -n | grep $mitmPort");
+    system("netstat -p tcp -n | grep :$mitmPort");
+  }
+
+  if (system("lsof -i :$mitmPort") == 0) {
+    die "cannot start mitmproxy because a process already exists on port $mitmPort";
   }
 
   my $childPid = fork();
@@ -1102,6 +1101,18 @@ sub RunVanillaTests
                         ("--dbname", "$dbName"));
 }
 
+if ($useMitmproxy) {
+    my $tries = 0;
+    until(system("lsof -i :$mitmPort") == 0) {
+        if ($tries > 60) {
+            die("waited for 60 seconds to start the mitmproxy, but it failed")
+        }
+        print("waiting: mitmproxy was not started yet\n");
+        sleep(1);
+        $tries++;
+    }
+}
+
 # Finally run the tests
 if ($vanillatest)
 {