fix(ext/node): fs.open and fs.openSync compatibility

[Tango992]

Notable changes:

• Introduces a separate op between Deno.open and node:fs.open.
• Removes redundant existenceCheckRequired and Deno.lstatSync calls, as the op layer already handles that when options.create_new is true and uses synchronous I/O when O_SYNC is passed.
• Allows passing custom flags to the op (e.g. O_SYNC).
• Addresses prefer-primordials lint rule.
• Allows parallel/test-fs-open.js test to pass. There are also several tests that have passed before that I added to the config.toml.

I decided to make a separate op function between the Deno fs and node, because Deno.OpenOptions currently doesn't allow passing numeric flags.

There's a caveat though, because the node:fs.constants are only correctly defined for macOS, passing these constants to the open function might not work as intended (excluding O_APPEND, O_CREAT, O_EXCL, O_TRUNC, O_RDONLY, O_WRONLY, O_RDWR). PR #30113 fixes this. Once merged it will allow parallel/test-fs-open-flags.js to pass.

I'm very open for any feedback.

Towards: #29972, #24236

[dsherret]

Great!