Bun cleanup

[deepy]

• [ ] Verify the tests
  • [ ] Verify that the tests actually test bun
  • [ ] Check that the test cases use either a downloaded or local copy of bun
  • [ ] Use the same bun version in tests that download bun
• [ ] Verify manually that download = true bun works
• [ ] Verify manually that download = false bun works
• [ ] Check if anything from BunExecRunner can be shared between the other ExecRunners
• [x] BunxTask accidentally uses npx

Extracted from https://github.com/node-gradle/gradle-node-plugin/issues/290#issuecomment-1774057375

[Jarred-Sumner]

nice