ww: unify directory package-test products

cmd/wcc/ww.h

@@ -613,8 +613,8 @@ struct Checker {
 					 * bodies and export compiler-private metadata,
 					 * but do not synthesize an entry. */
 	const char *test_module;	/* generated dispatcher support qualifier */
-	const char *test_target;	/* canonical target path used only as the
-				 * compiler-owned generated-main qualifier */
+	const char **test_targets; /* canonical generated-main target paths */
+	int	n_test_targets;
 	int	sep_mode;	/* -c package compilation: imported interfaces are
 				 * present, so absent members are hard export errors. */
 	Node	*synth_test_run;	/* exact compiler-generated support.run DOT;