[lldb] Remove ConstString from GetPluginNameStatic of some plugins

This patch deals with ObjectFile, ObjectContainer and OperatingSystem
plugins. I'll convert the other types in separate patches.

In order to enable piecemeal conversion, I am leaving some ConstStrings
in the lowest PluginManager layers. I'll convert those as the last step.

Differential Revision: https://reviews.llvm.org/D112061

lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

@@ -334,15 +334,6 @@ void ObjectFileELF::Terminate() {
   PluginManager::UnregisterPlugin(CreateInstance);
 }
 
-lldb_private::ConstString ObjectFileELF::GetPluginNameStatic() {
-  static ConstString g_name("elf");
-  return g_name;
-}
-
-const char *ObjectFileELF::GetPluginDescriptionStatic() {
-  return "ELF object file reader.";
-}
-
 ObjectFile *ObjectFileELF::CreateInstance(const lldb::ModuleSP &module_sp,
                                           DataBufferSP &data_sp,
                                           lldb::offset_t data_offset,