Don't automatically exclude closure functions from potential removal of the stack overflow check.

runtime/vm/flow_graph_compiler.cc

Index: runtime/vm/flow_graph_compiler.cc
diff --git a/runtime/vm/flow_graph_compiler.cc b/runtime/vm/flow_graph_compiler.cc
index 0c18be77c3c3da8ecc7fd71023b2477c2d9d0a9e..5bc26afbe351bbf8c6139ba8e54caccdea648d83 100644
--- a/runtime/vm/flow_graph_compiler.cc
+++ b/runtime/vm/flow_graph_compiler.cc
@@ -278,9 +278,7 @@ void FlowGraphCompiler::InitCompiler() {
   block_info_.Clear();
   // Conservative detection of leaf routines used to remove the stack check
   // on function entry.
-  bool is_leaf = !parsed_function().function().IsClosureFunction()
-      && is_optimizing()
-      && !flow_graph().IsCompiledForOsr();
+  bool is_leaf = is_optimizing() && !flow_graph().IsCompiledForOsr();
   // Initialize block info and search optimized (non-OSR) code for calls
   // indicating a non-leaf routine and calls without IC data indicating
   // possible reoptimization.