Core htmx perf Tests

• history implementation should be fast25ms ‣

  // create an entry with a large content string (256k) and see how fast we can write and read it
  // to local storage as a single entry
  var entry = { url: stringRepeat('x', 32), content: stringRepeat('x', 256 * 1024) }
  var array = []
  for (var i = 0; i < 10; i++) {
    array.push(entry)
  }
  var start = performance.now()
  var string = JSON.stringify(array)
  localStorage.setItem(HTMX_HISTORY_CACHE_NAME, string)
  var reReadString = localStorage.getItem(HTMX_HISTORY_CACHE_NAME)
  var finalJson = JSON.parse(reReadString)
  var end = performance.now()
  var timeInMs = end - start
  chai.assert(timeInMs < 300, 'Should take less than 300ms on most platforms')

• history snapshot cleaning should be fast17ms ‣

  var size = 5 * 1024 // ~350K in size, about the size of CNN's body tag :p
  var workArea = getWorkArea()
  var html = "<div class='foo bar'>Yay, really large HTML documents are fun!</div>\n"
  html = stringRepeat(html, size)
  workArea.insertAdjacentHTML('beforeend', html)
  var start = performance.now()
  htmx._('cleanInnerHtmlForHistory')(workArea)
  var end = performance.now()
  var timeInMs = end - start
  chai.assert(timeInMs < 50, 'Should take less than 50ms on most platforms')