[cleanup] Remove dead {native_function_map} context slot.

R=jkummerow@chromium.org

Change-Id: I961f77eb5e99a3d709aa5e948602a925f57ae090
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1617246Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61612}

src/contexts.h

@@ -300,7 +300,6 @@ enum ContextLookupFlags {
   V(STRING_FUNCTION_INDEX, JSFunction, string_function)                        \
   V(STRING_FUNCTION_PROTOTYPE_MAP_INDEX, Map, string_function_prototype_map)   \
   V(SYMBOL_FUNCTION_INDEX, JSFunction, symbol_function)                        \
-  V(NATIVE_FUNCTION_MAP_INDEX, Map, native_function_map)                       \
   V(WASM_EXCEPTION_CONSTRUCTOR_INDEX, JSFunction, wasm_exception_constructor)  \
   V(WASM_GLOBAL_CONSTRUCTOR_INDEX, JSFunction, wasm_global_constructor)        \
   V(WASM_INSTANCE_CONSTRUCTOR_INDEX, JSFunction, wasm_instance_constructor)    \

src/heap/factory.cc

@@ -2436,8 +2436,7 @@ Handle<JSFunction> Factory::NewFunction(const NewFunctionArgs& args) {
         (*map == *isolate()->sloppy_function_without_prototype_map()) ||
         (*map == *isolate()->sloppy_function_with_readonly_prototype_map()) ||
         (*map == *isolate()->strict_function_map()) ||
-        (*map == *isolate()->strict_function_without_prototype_map()) ||
-        (*map == *isolate()->native_function_map()));
+        (*map == *isolate()->strict_function_without_prototype_map()));
   }
 #endif