vfs: apply open(2) effects to ZipProvider handles

[pipobscure]

vfs: apply open(2) effects to ZipProvider handles

A ZipProvider handle keeps its content in memory and adds the entry to
the archive when it is closed, and only if something was written. The
effects a real open(2) has at open time are therefore lost, and so is
the metadata the entry already carried:

• open(path, 'w') followed by close() neither truncates an existing
  entry nor creates a missing one; the same holds for "a" on a missing
  file. Tools that touch or truncate by open-then-close do nothing.
• Rewriting an entry (append, or an in-place write through "r+") re-adds
  it with the mode argument open() received (fs's default 0o666),
  not the mode the entry had, so a 0o755 script silently loses its
  executable bit.
• fstat on a handle reports that same open() mode and the current
  time instead of the entry's mode and modification time.
• Renaming a file onto an existing directory succeeds and leaves a name
  that is both a file and a directory; real file systems refuse with
  EISDIR.

This adds a test for each of these against a mounted ZipBuffer, stating
the real-fs outcome as the expectation.

Proposed solution: mark the handle dirty at open time when the flags
imply creation or truncation, so close always commits; carry the
existing entry's mode and modification time on the handle, use them
for fstat and for the re-added entry, and only fall back to the
open() mode for a newly created entry; and reject rename onto an
existing directory with EISDIR before touching the archive.

Note: Since these are gaps/defects in existing functionality, I decided to create the failing tests first (first commit) and then add the fix/solution as a second commit. That way whoever wants to review this can first prove out the issue, before applying the solution.

This goes with the VFS work by @mcollina and the bug-fix PRs by @trivikr.

[codecov]

Codecov Report

❌ Patch coverage is 93.10345% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.18%. Comparing base (7991140) to head (a88f5b8).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/vfs/providers/ziparchive.js	93.10%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #65853      +/-   ##
==========================================
- Coverage   90.19%   90.18%   -0.01%     
==========================================
  Files         771      771              
  Lines      264622   264645      +23     
  Branches    50223    50242      +19     
==========================================
- Hits       238663   238661       -2     
- Misses      16965    16970       +5     
- Partials     8994     9014      +20     

Files with missing lines	Coverage Δ
lib/internal/vfs/providers/ziparchive.js	97.67% <93.10%> (-0.26%)	⬇️

... and 31 files with indirect coverage changes

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