Fix issue #3508

[damianpumar]

Fix issue #3508
Added runtime tests

To Reproduce before Fix:
https://svelte.dev/repl/e694e7e20f044deabaf55ff659a1e41e?version=3.9.2

Expected behavior
Expected that binding to an alias would be consistent with binding to an unaliased export.

[codecov-io]

Codecov Report

Merging #3573 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3573   +/-   ##
=======================================
  Coverage   50.25%   50.25%           
=======================================
  Files           1        1           
  Lines         197      197           
=======================================
  Hits           99       99           
  Misses         98       98

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[Conduitry]

I don't think this is quite the right solution. If, for some reason, the component had another unhoistable local variable with the same name as the alias of the export, this would cause that key to appear twice in the object returned by the instance function. I'm not sure what the right solution is though. It might require more sweeping changes.

(This PR is also now conflicted with master that #3539 has been merged in.)