test: expand golden C-codegen tests from 2 to 8 examples

Add golden tests for: structs, generics, algebraic_enums, enums,
methods, strings. Each test captures the expected C output from the
bootstrap compiler for regression detection.

Also remove leftover 'PARSER FIX V2 ACTIVE' debug print from parser.bux.

Makefile

@@ -78,7 +78,7 @@ selfhost: build
 
 .PHONY: test-golden
 
-GOLDEN_TESTS := hello fibonacci
+GOLDEN_TESTS := hello fibonacci structs generics algebraic_enums enums methods strings
 
 test-golden: build
 	@echo "=== Golden tests ==="