Create temp working directory for each libfuzzer invocation

[Porges]

No description provided.

[codecov-commenter]

Codecov Report

Merging #3603 (29d41b0) into main (d50fd48) will decrease coverage by 0.39%.
The diff coverage is 84.21%.

@@            Coverage Diff             @@
##             main    #3603      +/-   ##
==========================================
- Coverage   39.95%   39.57%   -0.39%     
==========================================
  Files         303      275      -28     
  Lines       37724    32740    -4984     
  Branches     1738     1738              
==========================================
- Hits        15073    12956    -2117     
+ Misses      22330    19463    -2867     
  Partials      321      321              

Files	Coverage Δ
src/agent/onefuzz-agent/src/validations.rs	0.00% <0.00%> (ø)
...nt/onefuzz-task/src/tasks/fuzz/libfuzzer/common.rs	83.97% <80.00%> (+1.35%)	⬆️
src/agent/onefuzz/src/libfuzzer.rs	79.16% <92.30%> (+0.66%)	⬆️

... and 56 files with indirect coverage changes