Better testing infrastructure; Initial exports/imports/re-exports

tests/compiler/reexport.ts

@@ -0,0 +1,7 @@
+export { add, renamed_sub } from "./export";
+
+import { add as imported_add, renamed_sub as imported_sub } from "./export";
+
+export { imported_add as renamed_add, imported_sub as rerenamed_sub };
+
+imported_add(1, 2) + imported_sub(3, 4);