Properly construct namespace when dynamically importing chunks with facades in default export mode

[lukastaegert]

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

List any relevant issue numbers:
Resolves #3708

Description

When a module was dynamically imported that formed the entry point of a chunk and that chunk had a facade chunk and this happened in AMD or CJS format where the chunk was in default export mode, THEN Rollup would not properly form a namespace to wrap the import as the default of an object. Kindof hard to explain, but here is the fix.

[rollup-bot]

Thank you for your contribution! ❤️

You can try out this pull request locally by installing Rollup via

npm install rollup/rollup#gh-3708-dynamic-import-default-mode-facade

or load it into the REPL:
https://rollupjs.org/repl/?circleci=12436

[codecov]

Codecov Report

Merging #3709 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #3709   +/-   ##
=======================================
  Coverage   96.80%   96.80%           
=======================================
  Files         183      183           
  Lines        6319     6320    +1     
  Branches     1842     1843    +1     
=======================================
+ Hits         6117     6118    +1     
  Misses        105      105           
  Partials       97       97           

Impacted Files	Coverage Δ
src/Chunk.ts	100.00% <100.00%> (ø)

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