test: rename regression tests with descriptive file names

Rename test-fs-truncate-GH-6233 to test-fs-truncate-clear-file-zero
Rename test-process-exit-GH-12322 to test-process-exit-flaky-handler

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

test/parallel/test-fs-truncate-GH-6233.js → test/parallel/test-fs-truncate-clear-file-zero.js

@@ -21,11 +21,15 @@
 
 'use strict';
 const common = require('../common');
+const tmpdir = require('../common/tmpdir');
+
+// This test ensures that `fs.truncate` opens the file with `r+` and not `w`,
+// which had earlier resulted in the target file's content getting zeroed out.
+// https://github.com/nodejs/node-v0.x-archive/issues/6233
+
 const assert = require('assert');
 const fs = require('fs');
 
-const tmpdir = require('../common/tmpdir');
-
 const filename = `${tmpdir.path}/truncate-file.txt`;
 
 tmpdir.refresh();
@@ -42,8 +46,12 @@ tmpdir.refresh();
 {
   fs.writeFileSync(filename, '0123456789');
   assert.strictEqual(fs.readFileSync(filename).toString(), '0123456789');
-  fs.truncate(filename, 5, common.mustCall(function(err) {
-    assert.ifError(err);
-    assert.strictEqual(fs.readFileSync(filename).toString(), '01234');
-  }));
+  fs.truncate(
+    filename,
+    5,
+    common.mustCall(function(err) {
+      assert.ifError(err);
+      assert.strictEqual(fs.readFileSync(filename).toString(), '01234');
+    })
+  );
 }

test/parallel/test-process-exit-flaky-handler.js

@@ -0,0 +1,11 @@
+'use strict';
+require('../common');
+
+// This test ensures that no asynchronous operations are performed in the 'exit'
+// handler.
+// https://github.com/nodejs/node/issues/12322
+
+process.on('exit', () => {
+  setTimeout(process.abort, 0); // Should not run.
+  for (const start = Date.now(); Date.now() - start < 10;);
+});