Remove support for Object.observe

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index 33a9ef1aee2132fa5b8664422a49e43c02c96e44..66e3e413aaecb69372f1f800c5e1f03eb0019a96 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -2395,7 +2395,6 @@ void Bootstrapper::ExportExperimentalFromRuntime(Isolate* isolate,
 #define EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(id) \
   void Genesis::InitializeGlobal_##id() {}
 
-EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_object_observe)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_unicode_regexps)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_do_expressions)
 EMPTY_INITIALIZE_GLOBAL_FOR_FEATURE(harmony_iterator_close)
@@ -2953,8 +2952,6 @@ bool Genesis::InstallExperimentalNatives() {
   static const char* harmony_tailcalls_natives[] = {nullptr};
   static const char* harmony_unicode_regexps_natives[] = {
       "native harmony-unicode-regexps.js", nullptr};
-  static const char* harmony_object_observe_natives[] = {
-      "native harmony-object-observe.js", nullptr};
   static const char* harmony_sharedarraybuffer_natives[] = {
       "native harmony-sharedarraybuffer.js", "native harmony-atomics.js", NULL};
   static const char* harmony_simd_natives[] = {"native harmony-simd.js",