Roll Flutter Engine from ddd27077eb21 to b6f4f8dd4a56 (2 revisions) (#111673)

diff --git a/bin/internal/engine.version b/bin/internal/engine.version
index 9f23688..b3a9977 100644
--- a/bin/internal/engine.version
+++ b/bin/internal/engine.version
@@ -1 +1 @@
-ddd27077eb214fe6c2e3cbddc99e2b60c24642eb
+b6f4f8dd4a5647d0c6da39fce85ff380218a1d1f