Support Babel 7

[theKashey]

Due to babel/babel#7035 we cant name RHL as RHL in babel template. Lets call in reactHotLoader :)

[codecov-io]

Codecov Report

Merging #754 into next will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             next     #754   +/-   ##
=======================================
  Coverage   80.95%   80.95%           
=======================================
  Files          15       15           
  Lines         441      441           
  Branches       91       92    +1     
=======================================
  Hits          357      357           
+ Misses         67       66    -1     
- Partials       17       18    +1

Impacted Files	Coverage Δ
...ges/react-hot-loader/src/internal/getReactStack.js	60.37% <0%> (ø)	⬆️

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