feat: tempfile cleanup for RParser

[joydeep049]

Continuing my and @mastersans work, adding tempfile cleanup for all fuzzing scripts.
Will be working on this over the next few days.

@terriko @anthonyharrison

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.84%. Comparing base (d6cbe40) to head (b7278cf).
Report is 106 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3944      +/-   ##
==========================================
+ Coverage   75.41%   80.84%   +5.43%     
==========================================
  Files         808      820      +12     
  Lines       11983    12358     +375     
  Branches     1598     1670      +72     
==========================================
+ Hits         9037     9991     +954     
+ Misses       2593     1936     -657     
- Partials      353      431      +78     

Flag	Coverage Δ
longtests	75.86% <ø> (+0.45%)	⬆️
win-longtests	78.90% <ø> (?)

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[terriko]

Looking good, but I'm thinking I may have missed some things in the others that I'm noting here.

[terriko]

Looks good enough to merge, I'm going to open an issue about maybe changing some of the existing fuzzers to use longer prefixes on the temp dirs.