Don't call FastNewFunctionContextStub if context is bigger than kMaxRegularHeapObjectSize.

src/crankshaft/x64/lithium-codegen-x64.cc

Index: src/crankshaft/x64/lithium-codegen-x64.cc
diff --git a/src/crankshaft/x64/lithium-codegen-x64.cc b/src/crankshaft/x64/lithium-codegen-x64.cc
index 6ff918fd54b2b13b757df9db56e5249ef35db991..00c989787e086bf9ce26e92da9455a17dbf238ef 100644
--- a/src/crankshaft/x64/lithium-codegen-x64.cc
+++ b/src/crankshaft/x64/lithium-codegen-x64.cc
@@ -179,11 +179,16 @@ void LCodeGen::DoPrologue(LPrologue* instr) {
       __ CallRuntime(Runtime::kNewScriptContext);
       deopt_mode = Safepoint::kLazyDeopt;
     } else {
-      FastNewFunctionContextStub stub(isolate());
-      __ Set(FastNewFunctionContextDescriptor::SlotsRegister(), slots);
-      __ CallStub(&stub);
-      // Result of FastNewFunctionContextStub is always in new space.
-      need_write_barrier = false;
+      if (slots <= FastNewFunctionContextStub::kMaximumSlots) {
+        FastNewFunctionContextStub stub(isolate());
+        __ Set(FastNewFunctionContextDescriptor::SlotsRegister(), slots);
+        __ CallStub(&stub);
+        // Result of FastNewFunctionContextStub is always in new space.
+        need_write_barrier = false;
+      } else {
+        __ Push(rdi);
+        __ CallRuntime(Runtime::kNewFunctionContext);
+      }
     }
     RecordSafepoint(deopt_mode);