test: remove unneeded escaping in template strings

The no-useless-escape rule in ESLint did not previously flag certain
unnecessary escaping in template strings. These will be flagged in
ESLint 3.8.0.

PR-URL: https://github.com/nodejs/node/pull/9112
Reviewed-By: Teddy Katz <teddy.katz@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>

test/parallel/test-debugger-pid.js

@@ -43,7 +43,7 @@ interfacer.on('line', function(line) {
     }
   } else {
     line = line.replace(/^(debug> *)+/, '');
-    expected = `(node:${pid}) Target process: 655555 doesn\'t exist.`;
+    expected = `(node:${pid}) Target process: 655555 doesn't exist.`;
   }
 
   assert.strictEqual(expected, line);

test/parallel/test-tick-processor-cpp-core.js

@@ -20,7 +20,7 @@ const base = require('./tick-processor-base.js');
 base.runTest({
   pattern: /RunInDebugContext/,
   code: `function f() {
-           require(\'vm\').runInDebugContext(\'Debug\');
+           require('vm').runInDebugContext('Debug');
            setImmediate(function() { f(); });
          };
          f();`

test/parallel/test-vm-cached-data.js

@@ -6,7 +6,7 @@ const spawnSync = require('child_process').spawnSync;
 const Buffer = require('buffer').Buffer;
 
 function getSource(tag) {
-  return `(function ${tag}() { return \'${tag}\'; })`;
+  return `(function ${tag}() { return '${tag}'; })`;
 }
 
 function produce(source, count) {

test/sequential/test-child-process-execsync.js

@@ -48,7 +48,7 @@ var msgBuf = Buffer.from(msg + '\n');
 
 // console.log ends every line with just '\n', even on Windows.
 
-cmd = `"${process.execPath}" -e "console.log(\'${msg}\');"`;
+cmd = `"${process.execPath}" -e "console.log('${msg}');"`;
 
 ret = execSync(cmd);