Roll engine to 6f459e2f10ca77a1dceced8cba062f5760a05f8e

flutter/engine@6f459e2 Revert "Reapply "Some cleanups enabled by removing support for Dart 1" (#6216)"
flutter/engine@0ded891 Roll src/third_party/skia 1b5ece0f06f4..e70aed7066c6 (1 commits)
flutter/engine@4057327 Roll src/third_party/skia bd6595544171..1b5ece0f06f4 (22 commits)
flutter/engine@838eb3d Improve performance of performance overlay by caching.
flutter/engine@7ac3345 Remove root_surface_transformation from PaintContext

bin/internal/engine.version

diff --git a/bin/internal/engine.version b/bin/internal/engine.version
index 6d50621..b00d545 100644
--- a/bin/internal/engine.version
+++ b/bin/internal/engine.version
@@ -1 +1 @@
-565a19489a85a39d731560ad353437d1fb7698a5
+6f459e2f10ca77a1dceced8cba062f5760a05f8e

bin/internal/goldens.version

diff --git a/bin/internal/goldens.version b/bin/internal/goldens.version
index b844c0b..5f3d3fa 100644
--- a/bin/internal/goldens.version
+++ b/bin/internal/goldens.version
@@ -1 +1 @@
-130faab3aee8893fa165daecf4122cd0ea6bccf4
+73aaafada280dbc726c6bfab510dd7b46fc7e3be