test: cover extra return tokens in methods

tests/typecheck_method_compat_return_extra_tokens_bad.claro

@@ -0,0 +1,6 @@
+CLASS Player
+    HAS score NUMBER
+    TEACH total TAKES amount RETURNS NUMBER
+        RETURN amount extra
+    LEARNED
+END

tests/typecheck_method_return_extra_tokens_bad.claro

@@ -0,0 +1,6 @@
+CLASS Player
+    HAS score NUMBER
+    TEACH total RETURNS NUMBER
+        RETURN 1 extra
+    END
+END