test: refactor indexOf uses to es6 equivalents

refactor indexOf uses to es6 where applicable

Refs: #12586

Author: Bnaya

test/pummel/test-dtrace-jsstack.js

@@ -86,14 +86,14 @@ dtrace.on('exit', function(code) {
   for (let i = 0; i < lines.length; i++) {
     const line = lines[i];
 
-    if (line.indexOf(sentinel) === -1 || frames.length === 0)
+    if (!line.includes(sentinel) || frames.length === 0)
       continue;
 
     const frame = line.substr(line.indexOf(sentinel) + sentinel.length);
     const top = frames.shift();
 
-    assert.strictEqual(frame.indexOf(top), 0,
-                       `unexpected frame where ${top} was expected`);
+    assert.ok(frame.startsWith(top),
+              `unexpected frame where ${top} was expected`);
   }
 
   assert.strictEqual(frames.length, 0,

test/pummel/test-regress-GH-814.js

@@ -51,7 +51,7 @@ const tail = require('child_process').spawn('tail', ['-f', testFileName]);
 tail.stdout.on('data', tailCB);
 
 function tailCB(data) {
-  PASS = data.toString().indexOf('.') < 0;
+  PASS = !data.toString().includes('.');
 }
 
 

test/pummel/test-regress-GH-814_2.js

@@ -35,7 +35,7 @@ const tailProc = require('child_process').spawn('tail', ['-f', testFileName]);
 tailProc.stdout.on('data', tailCB);
 
 function tailCB(data) {
-  PASS = data.toString().indexOf('.') < 0;
+  PASS = !data.toString().includes('.');
 
   if (PASS) {
     //console.error('i');