Fix polyfills loading order

[Hypnosphi]

Issue: addons.js is loaded before polyfills in manager entry, which leads to issues in IE.

What I did

I put addons.js right after the polyfills

How to test

Open React and Vue kitchen sink apps in IE11

[codecov]

Codecov Report

Merging #1905 into master will not change coverage.
The diff coverage is 0%.

@@           Coverage Diff           @@
##           master    #1905   +/-   ##
=======================================
  Coverage   21.31%   21.31%           
=======================================
  Files         257      257           
  Lines        5737     5737           
  Branches      693      685    -8     
=======================================
  Hits         1223     1223           
- Misses       3990     4002   +12     
+ Partials      524      512   -12

Impacted Files	Coverage Δ
app/react/src/server/config.js	0% <0%> (ø)	⬆️
app/vue/src/server/config.js	0% <0%> (ø)	⬆️
lib/ui/src/modules/ui/containers/left_panel.js	25.71% <0%> (ø)	⬆️
lib/ui/src/modules/ui/libs/hierarchy.js	48.8% <0%> (ø)	⬆️
addons/info/src/components/Props.js	36.36% <0%> (ø)	⬆️
addons/info/src/components/PropTable.js	21% <0%> (ø)	⬆️
app/react-native/src/preview/story_kind.js	0% <0%> (ø)	⬆️
addons/storyshots/src/require_context.js	0% <0%> (ø)	⬆️
.../ui/src/modules/ui/components/left_panel/header.js	29.62% <0%> (ø)	⬆️
lib/ui/src/modules/ui/configs/handle_routing.js	28.04% <0%> (ø)	⬆️
... and 18 more

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[ndelangen]

Looks good, but will this help with the issue we're having in 3.3?

[Hypnosphi]

That's exactly what it addresses. In 3.3, addon-links requires glamorous, which uses Object.assign without adding a polyfill. That's why we don't observe this problem on master. The change makes sense on master as well though

[ndelangen]

I'm making a mental note to revisit this code later, because this code looks super fishy to me.

I would prefer to not have to inject entry points like this.

[ndelangen]

If you've tested this @Hypnosphi go ahead and merge!

[Hypnosphi]

One possible alternative is to unshift polyfill into both entries right before passing the config to webpack