4400 [google_maps_flutter] Clean Java test, consolidate Marker example. (cla: yes, waiting for tree to go green, p: google_maps_flutter, platform-android)

4401 [webview_flutter] Update webview platform interface with new methods for running JavaScript. (cla: yes, waiting for tree to go green, p: webview_flutter)

4402 [webview_flutter] Update webview packages for Android and iOS to implement runJavascript and runJavascriptReturningResult. (cla: yes, p: webview_flutter, platform-ios, platform-android)

4404 [webview_flutter] Add zoomEnabled to webview flutter platform interface (cla: yes, p: webview_flutter)

4405 [ci] Remove obsolete Dockerfile (cla: yes, waiting for tree to go green)