LibJS: Rename Environment Records so they match the spec :^)

This patch makes the following name changes:

- ScopeObject => EnvironmentRecord
- LexicalEnvironment => DeclarativeEnvironmentRecord
- WithScope => ObjectEnvironmentRecord

Userland/Libraries/LibJS/Runtime/ObjectEnvironmentRecord.cpp

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibJS/AST.h>
+#include <LibJS/Runtime/ObjectEnvironmentRecord.h>
+
+namespace JS {
+
+ObjectEnvironmentRecord::ObjectEnvironmentRecord(Object& object, EnvironmentRecord* parent_scope)
+    : EnvironmentRecord(parent_scope)
+    , m_object(object)
+{
+}
+
+void ObjectEnvironmentRecord::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(&m_object);
+}
+
+Optional<Variable> ObjectEnvironmentRecord::get_from_scope(const FlyString& name) const
+{
+    auto value = m_object.get(name);
+    if (value.is_empty())
+        return {};
+    return Variable { value, DeclarationKind::Var };
+}
+
+void ObjectEnvironmentRecord::put_to_scope(const FlyString& name, Variable variable)
+{
+    m_object.put(name, variable.value);
+}
+
+bool ObjectEnvironmentRecord::delete_from_scope(FlyString const& name)
+{
+    return m_object.delete_property(name);
+}
+
+bool ObjectEnvironmentRecord::has_this_binding() const
+{
+    return parent()->has_this_binding();
+}
+
+Value ObjectEnvironmentRecord::get_this_binding(GlobalObject& global_object) const
+{
+    return parent()->get_this_binding(global_object);
+}
+
+}