Clean up globals

Summary: This diff is some boyscouting on cleaning up our globals, and stop using them inconsistently icmw global or window

Reviewed By: aigoncharov

Differential Revision: D33171108

fbshipit-source-id: 400893e5f31523631a7ab6fda428524c751901f1

desktop/flipper-ui-browser/src/initializeRenderHost.tsx

@@ -14,7 +14,7 @@ export function initializeRenderHost(
   flipperServer: FlipperServer,
   flipperServerConfig: FlipperServerConfig,
 ) {
-  window.FlipperRenderHostInstance = {
+  FlipperRenderHostInstance = {
     readTextFromClipboard() {
       // TODO:
       return undefined;