Fix all in file for import fix

Issue tracking #14549 for the import fix case. This will be more difficult than others because we'll need to add code to keep track of the imports we're about to add so they can be combined.

[robyoder]

@Andy-MS, in the description for PR #20338 you said that it "Does not fix" this issue, but GH only reads the fix [issue] piece of that and auto-closed this. Should this still be open?

d'oh, thanks.