Deprecate Math object in corelib in favor of dart:math library.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index af8695abcf43b802c1adeeeed8abc8553a5c65a3..7df5a6b01e7491eef4ba9b1a5f0ae07b85336d6f 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -858,7 +858,6 @@ RawError* Object::Init(Isolate* isolate) {
     return error.raw();
   }
   const Script& math_script = Script::Handle(Bootstrap::LoadMathScript(false));
-  Library::InitMathLibrary(isolate);
   const Library& math_lib = Library::Handle(Library::MathLibrary());
   ASSERT(!math_lib.IsNull());
   error = Bootstrap::Compile(math_lib, math_script);
@@ -6186,6 +6185,10 @@ void Library::InitCoreLibrary(Isolate* isolate) {
   core_impl_lib.Register();
   core_lib.AddImport(core_impl_lib);
   core_impl_lib.AddImport(core_lib);
+  Library::InitMathLibrary(isolate);
+  const Library& math_lib = Library::Handle(Library::MathLibrary());
+  core_lib.AddImport(math_lib);
+  core_impl_lib.AddImport(math_lib);
   isolate->object_store()->set_root_library(Library::Handle());
 
   // Hook up predefined classes without setting their library pointers. These