fix(page): page.click should work with disabled javascript (#2907)

Unfortunately, disabling javascript in page prevents any microtasks
to be executed even from puppeteer-originating javascript. As a
result, the IntersectionObserver hack we use to conditionally
scroll into view doesn't work.

To workaround this, we start always scrolling before clicking if
page's javascript is disabled.

Fixes #2898

lib/Page.js

@@ -88,6 +88,7 @@ class Page extends EventEmitter {
     this._ignoreHTTPSErrors = ignoreHTTPSErrors;
     this._coverage = new Coverage(client);
     this._defaultNavigationTimeout = 30000;
+    this._javascriptEnabled = true;
 
     this._screenshotTaskQueue = screenshotTaskQueue;
 
@@ -714,6 +715,9 @@ class Page extends EventEmitter {
    * @param {boolean} enabled
    */
   async setJavaScriptEnabled(enabled) {
+    if (this._javascriptEnabled === enabled)
+      return;
+    this._javascriptEnabled = enabled;
     await this._client.send('Emulation.setScriptExecutionDisabled', { value: !enabled });
   }