[roll] Roll Clang toolchain

Update Clang to revision bf0e3dfee52b8515aa95cde6239d0ba4ff3bac5d

Test: CQ
Change-Id: I341850bf4e1791089dfba3d751c194afa1b27bff
diff --git a/fuchsia.ensure b/fuchsia.ensure
index 9dda026..75537c2 100644
--- a/fuchsia.ensure
+++ b/fuchsia.ensure
@@ -35,7 +35,7 @@
 
 # Clang
 @Subdir clang
-fuchsia/clang/${platform} git_revision:4ad2908c9b4b485a0bf683f62a68e22f040b9f61
+fuchsia/clang/${platform} git_revision:bf0e3dfee52b8515aa95cde6239d0ba4ff3bac5d
 
 # Go
 @Subdir go