Fix potential flake in the new test

Author: pimterry

test/parallel/test-http-upgrade-server-with-body.mjs

@@ -29,6 +29,9 @@ async function createServer({ expectedBodyLength }) {
     // Collect the raw protocol data and check it:
     socket.on('data', common.mustCall((d) => {
       socketData = Buffer.concat([socketData, d]);
+    }));
+
+    socket.on('end', common.mustCall(() => {
       assert.strictEqual(socketData.toString(), 'upgrade head\npost-upgrade message');
       socket.end();
     }));
@@ -65,9 +68,9 @@ async function testUpgradeWithBody() {
 
   // Send more data after connection is confirmed:
   conn.write('\npost-upgrade message');
+  conn.end();
 
   await new Promise((resolve) => conn.on('end', resolve));
-  conn.end();
 
   server.close();
 }
@@ -110,9 +113,9 @@ async function testUpgradeWithLargeBody() {
 
   // Send more data after connection is confirmed:
   conn.write('\npost-upgrade message');
+  conn.end();
 
   await new Promise((resolve) => conn.on('end', resolve));
-  conn.end();
 
   server.close();
 }
@@ -145,9 +148,9 @@ async function testUpgradeWithUnreadBody() {
 
   // Send more data after connection is confirmed:
   conn.write('\npost-upgrade message');
+  conn.end();
 
   await new Promise((resolve) => conn.on('end', resolve));
-  conn.end();
 
   server.close();
 }
@@ -192,9 +195,9 @@ async function testUpgradeWithUnreadLargeBody() {
 
   // Send more data after connection is confirmed:
   conn.write('\npost-upgrade message');
+  conn.end();
 
   await new Promise((resolve) => conn.on('end', resolve));
-  conn.end();
 
   server.close();