feat: transparent class wrapping

[theKashey]

WIP

• moves class wrapper to a fiber level removing a parasite side effect from a user level.

This is a major milestone for v5 and removes one of the biggest RHL's sideeffect type comparison - #304

State before

hot-loader/react-dom introduces controller type comparison. We injected a few things to react-dom

• hotCleanup, to cleanup hooks rendering
• hotRenderWithHooks, to be able to render hooks in hotReplacementRender
• setHotElementComparator, to control type comparison, injected into reconcileSingleElement

New

This PR adds one more injection

• setHotTypeResolver injected into createFiberFromTypeAndProps

How it works

• no more user-space proxying
• Elements are passed to as-is, so <Type/>.type==Type both for FC(worked before), and now for Classes
• On fiber creation we are replacing the original type but a proxy
• hotElementComparator, which compares fiber node with element now compares proxy with the original type, and have to wrap element to perform comparison.

This is a replacement for #1138

Left to do

• changing hook order still throws an error
• classes are still could not be fully updated due to unrepeatable constructors.

I recon the second issue could be if not skipped, then deprecated due to the hooks.

[codecov-io]

Codecov Report

Merging #1261 into master will decrease coverage by 0.22%.
The diff coverage is 82.75%.

@@            Coverage Diff            @@
##           master   #1261      +/-   ##
=========================================
- Coverage   80.83%   80.6%   -0.23%     
=========================================
  Files          37      37              
  Lines        1273    1279       +6     
  Branches      329     332       +3     
=========================================
+ Hits         1029    1031       +2     
- Misses        191     194       +3     
- Partials       53      54       +1

Impacted Files	Coverage Δ
src/reconciler/componentComparator.js	9.37% <50%> (-0.15%)	⬇️
src/reactHotLoader.js	70.88% <85.18%> (-2.09%)	⬇️

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[codecov-io]

Codecov Report

Merging #1261 into master will decrease coverage by 0.21%.
The diff coverage is 82.14%.

@@            Coverage Diff             @@
##           master    #1261      +/-   ##
==========================================
- Coverage   80.83%   80.62%   -0.22%     
==========================================
  Files          37       37              
  Lines        1273     1321      +48     
  Branches      329      347      +18     
==========================================
+ Hits         1029     1065      +36     
- Misses        191      201      +10     
- Partials       53       55       +2

Impacted Files	Coverage Δ
src/reconciler/componentComparator.js	9.37% <50%> (-0.15%)	⬇️
src/reactHotLoader.js	70.51% <84.61%> (-2.47%)	⬇️
src/AppContainer.prod.js	50% <0%> (-50%)	⬇️
src/hot.prod.js	71.42% <0%> (-28.58%)	⬇️
src/babel.prod.js	91.54% <0%> (-0.76%)	⬇️

---

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[theKashey]

@gaearon - I need your eye on this. This mitigates the major RHL issue, but injects more and more code into react internals.