Ensure tests test error type

[joshwd36]

This Pull Request ensures tests that catch errors are testing the error type as well as just the message, as mentioned in this PR.

[codecov]

Codecov Report

Merging #563 into master will increase coverage by 0.07%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #563      +/-   ##
==========================================
+ Coverage   69.30%   69.37%   +0.07%     
==========================================
  Files         172      172              
  Lines       10580    10580              
==========================================
+ Hits         7332     7340       +8     
+ Misses       3248     3240       -8     

Impacted Files	Coverage Δ
boa/src/builtins/bigint/tests.rs	100.00% <100.00%> (ø)
boa/src/builtins/object/tests.rs	100.00% <100.00%> (ø)
boa/src/exec/operator/tests.rs	100.00% <100.00%> (ø)
boa/src/exec/tests.rs	100.00% <100.00%> (ø)
boa/src/builtins/error/type.rs	76.19% <0.00%> (+19.04%)	⬆️
boa/src/builtins/error/reference.rs	76.19% <0.00%> (+19.04%)	⬆️

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[Razican]

Perfect, thanks! :)