Roll engine dcbc8a820733..9e315e64659e (3 commits) (#21979)

https://github.com/flutter/engine/compare/dcbc8a820733...9e315e64659e

git log dcbc8a820733..9e315e64659e --no-merges --oneline
9e315e646 Remove entries from dart_vm_entry_points.txt and use annotations (flutter/engine#6226)
cdbe21466 Update test .gitignore (flutter/engine#6272)
dbfa8276d [fuchsia] Fixes for the Fuchsia build (flutter/engine#6273)


The AutoRoll server is located here: https://autoroll.skia.org/r/flutter-engine-flutter-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.