Revert "Roll engine to 834d6eb02988e7f2c44eda05cec908378a1a9138" (#14671)

* Revert "Roll engine to 834d6eb02988e7f2c44eda05cec908378a1a9138 (#14664)"

This reverts commit c19fbe86ddf9a82e848bcf8c7caf8a233965d514.
Reason: timeouts while doing hot reload in hot_mode_dev_cycle__preview_dart_2_benchmark.

bin/internal/engine.version

diff --git a/bin/internal/engine.version b/bin/internal/engine.version
index f734381..5dadd8a 100644
--- a/bin/internal/engine.version
+++ b/bin/internal/engine.version
@@ -1 +1 @@
-834d6eb02988e7f2c44eda05cec908378a1a9138
+f5a4a9378740c3d5996583a9ed1f7e28ff08ee85