avoid generating native code if only output ji file (#48431)

(cherry picked from commit 2eeefbe)

Author: vtjnash

src/precompile.c

@@ -114,8 +114,9 @@ JL_DLLEXPORT void jl_write_compiler_output(void)
     ios_t *s = NULL;
     ios_t *z = NULL;
     int64_t srctextpos = 0 ;
-    jl_create_system_image(&native_code, jl_options.incremental ? worklist : NULL, emit_split,
-                           &s, &z, &udeps, &srctextpos);
+    jl_create_system_image(emit_native ? &native_code : NULL,
+                           jl_options.incremental ? worklist : NULL,
+                           emit_split, &s, &z, &udeps, &srctextpos);
 
     if (!emit_split)
         z = s;

src/staticdata.c

@@ -2616,7 +2616,7 @@ JL_DLLEXPORT void jl_create_system_image(void **_native_data, jl_array_t *workli
     if (worklist) {
         mod_array = jl_get_loaded_modules();  // __toplevel__ modules loaded in this session (from Base.loaded_modules_array)
         // Generate _native_data`
-        if (jl_options.outputo || jl_options.outputbc || jl_options.outputunoptbc || jl_options.outputasm) {
+        if (_native_data != NULL) {
             jl_prepare_serialization_data(mod_array, newly_inferred, jl_worklist_key(worklist),
                                           &extext_methods, &new_specializations, NULL, NULL, NULL);
             jl_precompile_toplevel_module = (jl_module_t*)jl_array_ptr_ref(worklist, jl_array_len(worklist)-1);
@@ -2635,7 +2635,7 @@ JL_DLLEXPORT void jl_create_system_image(void **_native_data, jl_array_t *workli
             checksumpos_ff = checksumpos;
         }
     }
-    else {
+    else if (_native_data != NULL) {
         *_native_data = jl_precompile(jl_options.compile_enabled == JL_OPTIONS_COMPILE_ALL);
     }
 
@@ -2656,9 +2656,11 @@ JL_DLLEXPORT void jl_create_system_image(void **_native_data, jl_array_t *workli
         }
         datastartpos = ios_pos(ff);
     }
-    native_functions = *_native_data;
+    if (_native_data != NULL)
+        native_functions = *_native_data;
     jl_save_system_image_to_stream(ff, worklist, extext_methods, new_specializations, method_roots_list, ext_targets, edges);
-    native_functions = NULL;
+    if (_native_data != NULL)
+        native_functions = NULL;
     // make sure we don't run any Julia code concurrently before this point
     // Re-enable running julia code for postoutput hooks, atexit, etc.
     jl_gc_enable_finalizers(ct, 1);