Notify the analyzer of deleted files

[jakemac53]

Related to dart-lang/source_gen#682.

Deleted files were never getting a changeFile call and so they were still available in the analyzer. This exposed in particular old generated part files to subsequent builds which could cause weird errors.

[github-actions]

Package publishing

Package	Version	Status	Publish tag (post-merge)
package:build_runner	2.4.7-dev	ready to publish	build_runner-v2.4.7-dev
package:build_config	1.1.2-dev	ready to publish	build_config-v1.1.2-dev
package:build_daemon	4.0.1-dev	ready to publish	build_daemon-v4.0.1-dev
package:build_runner_core	7.2.11	already published at pub.dev
package:build_web_compilers	4.0.5	already published at pub.dev
package:build_modules	5.0.4	already published at pub.dev
package:build_resolvers	2.4.1-wip	WIP (no publish necessary)
package:build_test	2.2.1	already published at pub.dev
package:scratch_space	1.0.2	already published at pub.dev
package:build	2.4.2-wip	WIP (no publish necessary)

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.