[lldb][Core] Remove dead codepath in Mangled

Summary:
Objective-C names are stored in m_demangled, not in m_mangled. The
method in the condition will never return true.

Differential Revision: https://reviews.llvm.org/D79823

lldb/source/Core/Mangled.cpp

@@ -413,8 +413,6 @@ lldb::LanguageType Mangled::GuessLanguage() const {
     const char *mangled_name = mangled.GetCString();
     if (CPlusPlusLanguage::IsCPPMangledName(mangled_name))
       return lldb::eLanguageTypeC_plus_plus;
-    else if (ObjCLanguage::IsPossibleObjCMethodName(mangled_name))
-      return lldb::eLanguageTypeObjC;
   } else {
     // ObjC names aren't really mangled, so they won't necessarily be in the
     // mangled name slot.