fix(typescript-estree): ensure parent pointers are set

[bradzacher]

Fixes #1125

I (stupidly) forgot to mirror the code exactly when I set up the short-circuit return.

[typescript-eslint]

Thanks for the PR, @bradzacher!

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[codecov]

Codecov Report

Merging #1129 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #1129      +/-   ##
==========================================
+ Coverage   94.07%   94.07%   +<.01%     
==========================================
  Files         120      120              
  Lines        5214     5217       +3     
  Branches     1443     1443              
==========================================
+ Hits         4905     4908       +3     
  Misses        177      177              
  Partials      132      132

Impacted Files	Coverage Δ
...pt-estree/src/create-program/createWatchProgram.ts	93.29% <100%> (+0.12%)	⬆️