[lldb] Make exe_ctx an optional argument in OptionValueProperties (NFC)

The majority of call sites are nullptr as the execution context.
Refactor OptionValueProperties to make the argument optional and
simplify all the callers.

lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp

@@ -91,13 +91,13 @@ public:
 
   llvm::Triple::EnvironmentType ABI() const {
     return (llvm::Triple::EnvironmentType)m_collection_sp
-        ->GetPropertyAtIndexAsEnumeration(nullptr, ePropertyABI)
+        ->GetPropertyAtIndexAsEnumeration(ePropertyABI)
         .value_or(llvm::Triple::UnknownEnvironment);
   }
 
   OptionValueDictionary *ModuleABIMap() const {
     return m_collection_sp->GetPropertyAtIndexAsOptionValueDictionary(
-        nullptr, ePropertyModuleABIMap);
+        ePropertyModuleABIMap);
   }
 };