Commit e5fe6b1 ("treewide: refactor vector usage code") accidentially dropped
the upvalue resolving logic from uc_vm_stack_push(), leading to unresolved
upvalues leaking into the script execution context.

-- File test.uc --
export let obj = { foo: true, bar: false };
-- End --

-- Testcase --
import * as test from "./files/test.uc";

printf("%.J\n", [
	type(test.obj),
	test.obj.foo
]);
-- End --

-- Args --
-R
-- End --

-- Expect stdout --
[
	"object",
	true
]
-- End --