Manually roll engine.version from 55223fa5a39 to 38f51b97647

An engine change broke Fuchsia smoke tests downstream in the Fuchsia
repository, revert was https://github.com/flutter/engine/commit/38f51b97647fdbe1cb87fe69e7ddc3da4d307dce.

I suspect this will break Fuchsia in the next roll so rolling the Engine revert into
the framework so we can cherry-pick it into the roll.
diff --git a/bin/internal/engine.version b/bin/internal/engine.version
index 8c2adc1..a5b8bd2 100644
--- a/bin/internal/engine.version
+++ b/bin/internal/engine.version
@@ -1 +1 @@
-55223fa5a396e7115967602b1ad139636903d0e9
+38f51b97647fdbe1cb87fe69e7ddc3da4d307dce