[richardlau]

Use process.execPath instead of relying on the shebang for src/dist-indexer.js and node being on the PATH.

---

Without this, we have this edge condition if the test is run directly when node is not on the PATH.

rlau:~/sandbox/github/nodejs-dist-indexer$ ~/.nvs/node/22.23.4/x64/bin/node test/dist-indexer.test.js
env: ‘node’: No such file or directory
▶ dist-indexer
  ✖ no arguments produces expected error message (40.826214ms)
✖ dist-indexer (41.387342ms)
ℹ tests 1
ℹ suites 1
ℹ pass 0
ℹ fail 1
ℹ cancelled 0
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 45.975528

✖ failing tests:

test at test/dist-indexer.test.js:7:3
✖ no arguments produces expected error message (40.826214ms)
  AssertionError [ERR_ASSERTION]: Expected values to be strictly deep-equal:
  + actual - expected

    Comparison {
  +   message: 'Command failed: /home/rlau/sandbox/github/nodejs-dist-indexer/src/dist-indexer.js\n' +
  +     'env: ‘node’: No such file or directory\n'
  -   message: /Missing --dist <directory> argument/
    }

      at TestContext.<anonymous> (/home/rlau/sandbox/github/nodejs-dist-indexer/test/dist-indexer.test.js:8:12)
      at Test.runInAsyncScope (node:async_hooks:214:14)
      at Test.run (node:internal/test_runner/test:1047:25)
      at Test.start (node:internal/test_runner/test:944:17)
      at node:internal/test_runner/test:1440:71
      at node:internal/per_context/primordials:466:82
      at new Promise (<anonymous>)
      at new SafePromise (node:internal/per_context/primordials:435:3)
      at node:internal/per_context/primordials:466:9
      at Array.map (<anonymous>) {
    generatedMessage: true,
    code: 'ERR_ASSERTION',
    actual: [Error],
    expected: [Object],
    operator: 'throws',
    diff: 'simple'
  }
rlau:~/sandbox/github/nodejs-dist-indexer$