test(cli): pass an url to cwd

This should fix failing on Windows

cli/main_test.ts

@@ -1,5 +1,6 @@
 import { assertEquals } from "@std/assert";
 import { stripAnsiCode } from "@std/fmt/colors";
+import { fromFileUrl } from "@std/path";
 import { describe, it } from "@std/testing/bdd";
 import dedent from "dedent";
 
@@ -11,13 +12,11 @@ interface CommandResult {
 
 async function molt(argstr: string): Promise<CommandResult> {
   const args = argstr.split(" ").filter((it) => it.length);
-
-  const main = new URL("./main.ts", import.meta.url).pathname;
-  const cwd = new URL("./fixtures", import.meta.url).pathname;
+  const main = fromFileUrl(new URL("./main.ts", import.meta.url));
 
   const { code, stderr, stdout } = await new Deno.Command("deno", {
     args: ["run", "-A", main, "--dry-run", ...args],
-    cwd,
+    cwd: new URL("./fixtures", import.meta.url),
   }).output();
 
   const format = (bytes: Uint8Array) =>