test: change var to let in test-trace-events files

test/parallel/test-trace-events-all.js

@@ -6,7 +6,7 @@ const fs = require('fs');
 const path = require('path');
 
 const CODE =
-  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1)';
+  'setTimeout(() => { for (let i = 0; i < 100000; i++) { "test" + i } }, 1)';
 
 const tmpdir = require('../common/tmpdir');
 tmpdir.refresh();

test/parallel/test-trace-events-async-hooks-dynamic.js

@@ -18,7 +18,7 @@ const path = require('path');
 const enable = `require("trace_events").createTracing(
 { categories: ["node.async_hooks"] }).enable();`;
 const code =
-  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1)';
+  'setTimeout(() => { for (let i = 0; i < 100000; i++) { "test" + i } }, 1)';
 
 const tmpdir = require('../common/tmpdir');
 const filename = path.join(tmpdir.path, 'node_trace.1.log');

test/parallel/test-trace-events-async-hooks-worker.js

@@ -16,7 +16,7 @@ const fs = require('fs');
 const path = require('path');
 
 const code =
-  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1)';
+  'setTimeout(() => { for (let i = 0; i < 100000; i++) { "test" + i } }, 1)';
 const worker =
 `const { Worker } = require('worker_threads');
 const worker = new Worker('${code}',

test/parallel/test-trace-events-async-hooks.js

@@ -7,7 +7,7 @@ const path = require('path');
 const util = require('util');
 
 const CODE =
-  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1)';
+  'setTimeout(() => { for (let i = 0; i < 100000; i++) { "test" + i } }, 1)';
 
 const tmpdir = require('../common/tmpdir');
 tmpdir.refresh();

test/parallel/test-trace-events-file-pattern.js

@@ -9,7 +9,7 @@ const path = require('path');
 tmpdir.refresh();
 
 const CODE =
-  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1)';
+  'setTimeout(() => { for (let i = 0; i < 100000; i++) { "test" + i } }, 1)';
 
 const proc = cp.spawn(process.execPath, [
   '--trace-events-enabled',

test/parallel/test-trace-events-metadata.js

@@ -6,7 +6,7 @@ const fs = require('fs');
 const path = require('path');
 
 const CODE =
-  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1);' +
+  'setTimeout(() => { for (let i = 0; i < 100000; i++) { "test" + i } }, 1);' +
   'process.title = "foo"';
 
 const tmpdir = require('../common/tmpdir');

test/parallel/test-trace-events-none.js

@@ -6,7 +6,7 @@ const fs = require('fs');
 const path = require('path');
 
 const CODE =
-  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1)';
+  'setTimeout(() => { for (let i = 0; i < 100000; i++) { "test" + i } }, 1)';
 
 const tmpdir = require('../common/tmpdir');
 tmpdir.refresh();

test/parallel/test-trace-events-v8.js

@@ -6,7 +6,7 @@ const fs = require('fs');
 const path = require('path');
 
 const CODE =
-  'setTimeout(() => { for (var i = 0; i < 100000; i++) { "test" + i } }, 1)';
+  'setTimeout(() => { for (let i = 0; i < 100000; i++) { "test" + i } }, 1)';
 
 const tmpdir = require('../common/tmpdir');
 tmpdir.refresh();