Snapshot clean ups

- Don't call eval() in mock_runtime - not allowed - see js2c.py.
- Don't use v8_use_external_startup_data
- Move MakeSnapshot to snapshot_creator.cc
- Use logging.h in from_snapshot.cc

deno2/deno_internal.h

@@ -38,10 +38,6 @@ Deno* NewFromSnapshot(void* data, deno_sub_cb cb);
 void InitializeContext(v8::Isolate* isolate, v8::Local<v8::Context> context,
                        const char* js_filename, const char* js_source);
 
-v8::StartupData MakeSnapshot(v8::StartupData* prev_natives_blob,
-                             v8::StartupData* prev_snapshot_blob,
-                             const char* js_filename, const char* js_source);
-
 void AddIsolate(Deno* d, v8::Isolate* isolate);
 
 }  // namespace deno