video_core/ast: Make ShowCurrentState() take a string_view instead of std::string

Allows the function to be non-allocating in terms of the output string.

src/video_core/shader/ast.cpp

@@ -549,7 +549,7 @@ bool ASTManager::DirectlyRelated(const ASTNode& first, const ASTNode& second) co
     return min->GetParent() == max->GetParent();
 }
 
-void ASTManager::ShowCurrentState(std::string state) {
+void ASTManager::ShowCurrentState(std::string_view state) {
     LOG_CRITICAL(HW_GPU, "\nState {}:\n\n{}\n", state, Print());
     SanityCheck();
 }

src/video_core/shader/ast.h

@@ -332,7 +332,7 @@ public:
 
     void Decompile();
 
-    void ShowCurrentState(std::string state);
+    void ShowCurrentState(std::string_view state);
 
     void SanityCheck();