[lldb] Check for the mangled symbol name for objc_copyRealizedClassList_nolock

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.

Differential revision: https://reviews.llvm.org/D105136

(cherry picked from commit 71be4db)

Author: JDevlieghere

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

@@ -499,7 +499,7 @@ AppleObjCRuntimeV2::AppleObjCRuntimeV2(Process *process,
   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);