Fix Array.join when the array contains itself

[ahaoboy]

The documentation doesn't specify how the join function should handle cases where the array contains itself, but other engines treat it as an empty string.

let b = []
b[0] = b;
b[1] = b;
b[2] = b;

// expect output: ",,"
console.log(b.join(','))

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (26d14a8) 45.65% compared to head (3c6556a) 45.65%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3406   +/-   ##
=======================================
  Coverage   45.65%   45.65%           
=======================================
  Files         483      483           
  Lines       49498    49498           
=======================================
  Hits        22600    22600           
  Misses      26898    26898           

Files	Coverage Δ
boa_engine/src/builtins/array/mod.rs	76.34% <100.00%> (+0.09%)	⬆️

... and 2 files with indirect coverage changes

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[Razican]

It seems there are no Test262 tests for this behavior, so we should add a Rust test

[jedel1043]

Thanks for the contribution!

[HalidOdat]

Looks good to me! :)