Use PluginInstances instead of vector for Architecuture plugins

This was the only plugin type that was not using the PluginInstance
wrapper. It needs to use the PluginInstances to hook into the
enable/disable support.

Author: dmpots

lldb/source/Core/PluginManager.cpp

@@ -407,7 +407,7 @@ ABICreateInstance PluginManager::GetABICreateCallbackAtIndex(uint32_t idx) {
 #pragma mark Architecture
 
 typedef PluginInstance<ArchitectureCreateInstance> ArchitectureInstance;
-typedef std::vector<ArchitectureInstance> ArchitectureInstances;
+typedef PluginInstances<ArchitectureInstance> ArchitectureInstances;
 
 static ArchitectureInstances &GetArchitectureInstances() {
   static ArchitectureInstances g_instances;
@@ -417,25 +417,18 @@ static ArchitectureInstances &GetArchitectureInstances() {
 void PluginManager::RegisterPlugin(llvm::StringRef name,
                                    llvm::StringRef description,
                                    ArchitectureCreateInstance create_callback) {
-  GetArchitectureInstances().push_back({name, description, create_callback});
+  GetArchitectureInstances().RegisterPlugin(name, description, create_callback);
 }
 
 void PluginManager::UnregisterPlugin(
     ArchitectureCreateInstance create_callback) {
   auto &instances = GetArchitectureInstances();
-
-  for (auto pos = instances.begin(), end = instances.end(); pos != end; ++pos) {
-    if (pos->create_callback == create_callback) {
-      instances.erase(pos);
-      return;
-    }
-  }
-  llvm_unreachable("Plugin not found");
+  instances.UnregisterPlugin(create_callback);
 }
 
 std::unique_ptr<Architecture>
 PluginManager::CreateArchitectureInstance(const ArchSpec &arch) {
-  for (const auto &instances : GetArchitectureInstances()) {
+  for (const auto &instances : GetArchitectureInstances().GetSnapshot()) {
     if (auto plugin_up = instances.create_callback(arch))
       return plugin_up;
   }