Revert "Roll engine to pick up fix for windows preview-dart-2 tests"

This reverts commit dbd3eb678af12bf0e91a289dba4a400d05e523e0.

Commit above fixed initial problem with frontend_server on Windows, but caused another more explicit problem with gen_snapshot down the line.

bin/internal/engine.version

diff --git a/bin/internal/engine.version b/bin/internal/engine.version
index 4f32547..4d73f93 100644
--- a/bin/internal/engine.version
+++ b/bin/internal/engine.version
@@ -1 +1 @@
-1fb585810faacccf81d4aa4e5392c31e1593e031
+937bde8f98e64aa574f77049bc52e9c8e862c82c