Include main entrypoint in FLX snapshot checksum (#11762)
Include main entrypoint in FLX snapshot checksum (#11762)

During FLX snapshotting, changes to (or absence of) any of the following
should trigger re-snapshot:

  1. main() entrypoint source
  2. transitive closure of sources reachable from the entrypoint source
  3. the output snapshot
flutter/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter,flutter/flutter,Hixie/flutter,flutter/flutter,Hixie/flutter,tvolkert/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,flutter/flutter,Hixie/flutter,Hixie/flutter,tvolkert/flutter,Hixie/flutter,flutter/flutter,cbracken/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,Hixie/flutter,cbracken/flutter,Hixie/flutter,turnidge/flutter,cbracken/flutter,Hixie/flutter,turnidge/flutter,cbracken/flutter,cbracken/flutter,cbracken/flutter,turnidge/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,cbracken/flutter,turnidge/flutter,flutter/flutter,turnidge/flutter,tvolkert/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter