perf(core): skip unnecessary access call in fetchPackageFromCache

[merceyz]

What's the problem this PR addresses?

During the link step of an install the Cache will check if cache entries exists on disk even though it already checked that during the fetch step.

Ref #4057

How did you fix it?

Check if the cache entry is in markedFiles before checking the disk.

Benchmark results

On the gatsby benchmark this removes 1942 access syscalls

YARN_IGNORE_PATH=1 hyperfine -w 1 \
  "node ./cache.cjs --mode skip-build" \
  "node ./master.cjs --mode skip-build"
Benchmark 1: node ./cache.cjs --mode skip-build
  Time (mean ± σ):      1.621 s ±  0.009 s    [User: 2.344 s, System: 0.352 s]
  Range (min … max):    1.605 s …  1.637 s    10 runs

Benchmark 2: node ./master.cjs --mode skip-build
  Time (mean ± σ):      1.707 s ±  0.012 s    [User: 2.397 s, System: 0.429 s]
  Range (min … max):    1.692 s …  1.725 s    10 runs

Summary
  'node ./cache.cjs --mode skip-build' ran
    1.05 ± 0.01 times faster than 'node ./master.cjs --mode skip-build'

Checklist

• I have read the Contributing Guide.
• I have set the packages that need to be released for my changes to be effective.
• I will check that all automated PR checks pass before the PR gets reviewed.