test: rename regression tests with descriptive file names

Rename the tests appropriately alongside mentioning the subsystem
Also, make a few basic changes to make sure the tests conform to the standard test structure

1. Renamed test-regress-GH-io-1068 to test-tty-stdin-end
2. Renamed test-regress-GH-io-1811 to test-zlib-kmaxlength-rangeerror
3. Renamed test-regress-GH-node-9326 to test-kill-segfault-freebsd
4. Renamed test-timers-regress-GH-9765 to test-timers-setimmediate-infinite-loop
5. Renamed test-tls-pfx-gh-5100-regr to test-tls-pfx-authorizationerror
6. Renamed test-tls-regr-gh-5108 to test-tls-tlswrap-segfault

Fixes: #19105
Refs: #19105
Refs: https://github.com/nodejs/node/blob/master/doc/guides/writing-tests.md#test-structure

test/parallel/test-regress-GH-node-9326.js → test/parallel/test-kill-segfault-freebsd.js

@@ -1,5 +1,10 @@
 'use strict';
 require('../common');
+
+// This test ensures Node.js doesn't crash on hitting Ctrl+C in order to
+// terminate the currently running process (especially on FreeBSD).
+// https://github.com/nodejs/node-v0.x-archive/issues/9326
+
 const assert = require('assert');
 const child_process = require('child_process');
 

test/parallel/test-tls-pfx-authorizationerror.js

@@ -0,0 +1,42 @@
+'use strict';
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('node compiled without crypto.');
+const fixtures = require('../common/fixtures');
+
+// This test ensures that TLS does not fail to read a self-signed certificate
+// and thus throw an `authorizationError`.
+// https://github.com/nodejs/node/issues/5100
+
+const assert = require('assert');
+const tls = require('tls');
+
+const pfx = fixtures.readKey('agent1-pfx.pem');
+
+const server = tls
+  .createServer(
+    {
+      pfx: pfx,
+      passphrase: 'sample',
+      requestCert: true,
+      rejectUnauthorized: false
+    },
+    common.mustCall(function(c) {
+      assert.strictEqual(c.authorizationError, null);
+      c.end();
+    })
+  )
+  .listen(0, function() {
+    const client = tls.connect(
+      {
+        port: this.address().port,
+        pfx: pfx,
+        passphrase: 'sample',
+        rejectUnauthorized: false
+      },
+      function() {
+        client.end();
+        server.close();
+      }
+    );
+  });

test/parallel/test-tls-regr-gh-5108.js → test/parallel/test-tls-tlswrap-segfault.js

@@ -1,19 +1,21 @@
 'use strict';
 const common = require('../common');
-
 if (!common.hasCrypto)
   common.skip('missing crypto');
+const fixtures = require('../common/fixtures');
+
+// This test ensures that Node.js doesn't incur a segfault while accessing
+// TLSWrap fields after the parent handle was destroyed.
+// https://github.com/nodejs/node/issues/5108
 
 const assert = require('assert');
 const tls = require('tls');
-const fixtures = require('../common/fixtures');
 
 const options = {
   key: fixtures.readKey('agent1-key.pem'),
   cert: fixtures.readKey('agent1-cert.pem')
 };
 
-
 const server = tls.createServer(options, function(s) {
   s.end('hello');
 }).listen(0, function() {
@@ -26,7 +28,6 @@ const server = tls.createServer(options, function(s) {
   });
 });
 
-
 function putImmediate(client) {
   setImmediate(function() {
     if (client.ssl) {

test/parallel/test-tty-stdin-end.js

@@ -0,0 +1,7 @@
+'use strict';
+require('../common');
+
+// This test ensures that Node.js doesn't crash on `process.stdin.emit("end")`.
+// https://github.com/nodejs/node/issues/1068
+
+process.stdin.emit('end');

test/parallel/test-regress-GH-io-1811.js → test/parallel/test-zlib-kmaxlength-rangeerror.js

@@ -1,6 +1,10 @@
 'use strict';
-
 require('../common');
+
+// This test ensures that zlib throws a RangeError if the final buffer needs to
+// be larger than kMaxLength and concatenation fails.
+// https://github.com/nodejs/node/pull/1811
+
 const assert = require('assert');
 
 // Change kMaxLength for zlib to trigger the error without having to allocate