[turbofan] Don't try to inline our builtins.

src/compiler/js-inlining-heuristic.cc

Index: src/compiler/js-inlining-heuristic.cc
diff --git a/src/compiler/js-inlining-heuristic.cc b/src/compiler/js-inlining-heuristic.cc
index ec00e9bde412a7c8adbcc67ebb3b9237185df3e3..700d7467262dba0b1b18d54392f5113d336a41ef 100644
--- a/src/compiler/js-inlining-heuristic.cc
+++ b/src/compiler/js-inlining-heuristic.cc
@@ -48,6 +48,9 @@ Reduction JSInliningHeuristic::Reduce(Node* node) {
   // Built-in functions are handled by the JSBuiltinReducer.
   if (function->shared()->HasBuiltinFunctionId()) return NoChange();
 
+  // Don't inline builtins.
+  if (function->shared()->IsBuiltin()) return NoChange();
+
   // Quick check on source code length to avoid parsing large candidate.
   if (function->shared()->SourceSize() > FLAG_max_inlined_source_size) {
     return NoChange();