[builtins] TurboFan version of Array.prototype.forEach including fast path for FAST_ELEMENTS

src/flag-definitions.h

Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index d053ff7d28068e4df62d23fa9bc1b3b6f6d4738d..94561152782de335efd3914931322d4cf68c89cf 100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -257,6 +257,7 @@ DEFINE_BOOL(future, false,
 DEFINE_IMPLICATION(future, turbo)
 
 DEFINE_IMPLICATION(turbo, ignition_staging)
+DEFINE_IMPLICATION(turbo, enable_fast_array_builtins)
 
 // TODO(rmcilroy): Remove ignition-staging and set these implications directly
 // with the turbo flag.
@@ -644,6 +645,7 @@ DEFINE_BOOL(builtins_in_stack_traces, false,
             "show built-in functions in stack traces")
 
 // builtins.cc
+DEFINE_BOOL(enable_fast_array_builtins, false, "use optimized builtins")
 DEFINE_BOOL(allow_unsafe_function_constructor, false,
             "allow invoking the function constructor without security checks")