Fix many asan and ubsan reported issues

This allows most demos to run without any ubsan or asan errors. There
are still some things in thirdpart/ and some things in AudioServer that
needs a look but this fixes a lot of issues. This should help debug less
obvious issues, hopefully.

This fixes #25217 and fixes #25218

modules/gdscript/gdscript_parser.h

@@ -95,6 +95,7 @@ public:
 		}
 
 		DataType() :
+				kind(UNRESOLVED),
 				has_type(false),
 				is_constant(false),
 				is_meta_type(false),
@@ -168,6 +169,7 @@ public:
 			MultiplayerAPI::RPCMode rpc_mode;
 			int usages;
 		};
+
 		struct Constant {
 			Node *expression;
 			DataType type;