ESLint: Require 'use strict' header (#5334)

* Fix issues related to adding strict-mode

These issues are either just a different behavior in strict-mode,
changes to tests that expect specific lines, or hiding real errors.

Author: watson

benchmark/sirun/appsec-iast/insecure-bank.js

@@ -1,3 +1,5 @@
+'use strict'
+
 const http = require('http')
 const app = require('/opt/insecure-bank-js/app') // eslint-disable-line import/no-absolute-path
 

benchmark/sirun/appsec/insecure-bank.js

@@ -1,3 +1,5 @@
+'use strict'
+
 const http = require('http')
 const app = require('/opt/insecure-bank-js/app') // eslint-disable-line import/no-absolute-path
 

benchmark/sirun/encoding/index.js

@@ -1,3 +1,5 @@
+'use strict'
+
 const {
   ENCODER_VERSION
 } = process.env

benchmark/sirun/gc.js

@@ -1,3 +1,5 @@
+'use strict'
+
 const { createHistogram, PerformanceObserver } = require('perf_hooks')
 if (createHistogram) {
   const StatsD = require('./statsd')

benchmark/sirun/means.js

@@ -1,3 +1,5 @@
+'use strict'
+
 /* eslint-disable no-console */
 
 const chunks = []

benchmark/sirun/scope/index.js

@@ -1,3 +1,5 @@
+'use strict'
+
 const {
   DD_TRACE_SCOPE,
   COUNT

benchmark/sirun/shimmer-runtime/index.js

@@ -1,3 +1,5 @@
+'use strict'
+
 /* eslint-disable require-await */
 
 const shimmer = require('../../../packages/datadog-shimmer')

benchmark/sirun/shimmer-startup/index.js

@@ -1,3 +1,5 @@
+'use strict'
+
 /* eslint-disable require-await */
 
 const shimmer = require('../../../packages/datadog-shimmer')

benchmark/sirun/spans/spans.js

@@ -1,3 +1,5 @@
+'use strict'
+
 const tracer = require('../../..').init()
 
 tracer._tracer._processor.process = function process (span) {

benchmark/sirun/strip-unwanted-results.js

@@ -1,4 +1,5 @@
 #!/usr/bin/env node
+'use strict'
 
 const fs = require('fs')
 const path = require('path')