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.

tests/golden/algebraic_enums/bux.toml

@@ -0,0 +1,7 @@
+[Package]
+Name    = "algebraic_enums"
+Version = "0.1.0"
+Type    = "bin"
+
+[Build]
+Output = "Bin"