Adding a dependency with yarn while serving the app breaks ngcc generated files import

[yjaaidi]

🐞 Bug report

Command (mark with an x)

• new
• build
• serve
• test
• e2e
• generate
• add
• update
• lint
• xi18n
• run
• config
• help
• version
• doc

Is this a regression?

Yes, the previous version in which this bug was not present was: 8.2.14

Description

When running Angular 9 with ng serve then installing a dependency with yarn, yarn will overwrite angular dependencies' package.json files and remove __ivy_ngcc__ files generated by ngcc when ng serve starts.
This produces an error on ng serve as it can't find IVy generated files like ./node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js

Maybe ng serve could watch for these files and rebuild them if they disappear?

🔥 Exception or Error

ERROR in ./node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js
Module build failed: Error: ENOENT: no such file or directory, open '/Users/r/Desktop/demo/node_modules/@angular/core/__ivy_ngcc__/fesm2015/core.js'

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