[turbofan] Enable TurboFan when compiling JS runtime calls.

This should recover a part of the regression caused by 7f11fba7 (https://codereview.chromium.org/1739233002).

BUG=chromium:592692
LOG=N

Review URL: https://codereview.chromium.org/1793293003

Cr-Commit-Position: refs/heads/master@{#34783}

src/ast/ast-numbering.cc

@@ -268,7 +268,7 @@ void AstNumberingVisitor::VisitCallRuntime(CallRuntime* node) {
   ReserveFeedbackSlots(node);
   if (node->is_jsruntime()) {
     // Don't try to optimize JS runtime calls because we bailout on them.
-    DisableOptimization(kCallToAJavaScriptRuntimeFunction);
+    DisableCrankshaft(kCallToAJavaScriptRuntimeFunction);
   }
   node->set_base_id(ReserveIdRange(CallRuntime::num_ids()));
   VisitArguments(node->arguments());