[SymbolFile] SymbolFileDWARF::ParseLineTable should lock its module

As of svn rL367298, SymbolFileDWARF locks the module in many cases where
it needs to parse some aspect of the DWARF symbol file.
SymbolFileDWARF::ParseLineTable needs to lock the module because
SymbolVendor::ParseLineTable no longer locks it.

llvm-svn: 367358

lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

@@ -928,7 +928,7 @@ static void ParseDWARFLineTableCallback(dw_offset_t offset,
 }
 
 bool SymbolFileDWARF::ParseLineTable(CompileUnit &comp_unit) {
-  ASSERT_MODULE_LOCK(this);
+  std::lock_guard<std::recursive_mutex> guard(GetModuleMutex());
   if (comp_unit.GetLineTable() != nullptr)
     return true;