[lldb] Check for the mangled symbol name for objc_copyRealizedClassList_nolock

[JDevlieghere]

Summary

When we check whether the Objective-C SPI is available, we need to check
for the mangled symbol name. Unlike objc_copyRealizedClassList, which
is C exported, the nolock variant is not.

[jingham]

LGTM

lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp

: AppleObjCRuntime(process), m_objc_module_sp(objc_module_sp),
       m_loaded_objc_opt(false), m_non_pointer_isa_cache_up(),
       m_tagged_pointer_vendor_up(
           TaggedPointerVendorV2::CreateInstance(*this, objc_module_sp)),
       m_encoding_to_type_sp(), m_noclasses_warning_emitted(false),
       m_CFBoolean_values(), m_realized_class_generation_count(0) {
   static const ConstString g_gdb_object_getClass("gdb_object_getClass");
   m_has_object_getClass = HasSymbol(g_gdb_object_getClass);
   static const ConstString g_objc_copyRealizedClassList(
-      "objc_copyRealizedClassList_nolock");
+      "_ZL33objc_copyRealizedClassList_nolockPj");
   m_has_objc_copyRealizedClassList = HasSymbol(g_objc_copyRealizedClassList);
 
   RegisterObjCExceptionRecognizer(process);
 }
 
 bool AppleObjCRuntimeV2::GetDynamicTypeAndAddress(
     ValueObject &in_value, lldb::DynamicValueType use_dynamic,
     TypeAndOrName &class_type_or_name, Address &address,