perf(node/fs): faster existsSync when not exists

[dsherret]

% ./target/release/deno bench -A exists.bench.ts
Check file:https:///Users/david/dev/deno/exists.bench.ts
cpu: Apple M2 Pro
runtime: deno 1.38.4 (aarch64-apple-darwin)

file:https:///Users/david/dev/deno/exists.bench.ts
benchmark               time (avg)        iter/s             (min … max)       p75       p99      p995
------------------------------------------------------------------------ -----------------------------
std/existsSync          19.23 µs/iter      51,996.7  (17.21 µs … 348.29 µs)  19.29 µs  22.67 µs  24.25 µs
node:fs existsSync       6.24 µs/iter     160,376.3     (6.19 µs … 6.42 µs)   6.25 µs   6.42 µs   6.42 µs

Raises the point that we need to get std's existsSync to be faster.

[dsherret]

One other thing this fixes is previously this would supress permission errors.

[bartlomieju]

IIRC this was done on purpose, but seems fishy. @kt3k any idea here?

[dsherret]

If intentional, my guess would be to reduce permission prompts, but I don't think we should do that because it causes subtle bugs.

[kt3k]

Looks like it was for avoiding to throw 'Not a directory' error when called with non-existing dir denoland/deno_std#2494

[bartlomieju]

IIRC this was done on purpose, but seems fishy. @kt3k any idea here?

[bartlomieju]

LGTM