Reintroduce accidentally deleted "protected" keyword in SymbolFileDWARF (llvm#69990)

The "protected" was accidentally removed during refactoring of
SymbolFileDWARF. Reintroduce it and also make DWARFASTParser a friend
class since 040c4f4 was merged and
won't build without it, as it dependeds on a method which was made
public by accident.

Author: augusto2112

Diff for: lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h

@@ -82,6 +82,7 @@ class SymbolFileDWARF : public SymbolFileCommon {
   friend class DebugMapModule;
   friend class DWARFCompileUnit;
   friend class DWARFDIE;
+  friend class DWARFASTParser;
   friend class ::DWARFASTParserClang;
 
   // Static Functions
@@ -321,6 +322,7 @@ class SymbolFileDWARF : public SymbolFileCommon {
     m_file_index = file_index;
   }
 
+protected:
   typedef llvm::DenseMap<const DWARFDebugInfoEntry *, Type *> DIEToTypePtr;
   typedef llvm::DenseMap<const DWARFDebugInfoEntry *, lldb::VariableSP>
       DIEToVariableSP;