wrap the regress error for now

[jasonwilliams]

Regress panics on "Invalid character escape"s.
However on V8 and other JS engines these seem to be acceptable.

const a = /,\;/;

was causing issues in Boa, due to regress panicing and us not catching.
This PR now changes it to a SyntaxError, however this is a temporary fix, ideally it should be accepted.

Raised upstream:
ridiculousfish/regress#26

[codecov]

Codecov Report

Merging #1027 (66135bc) into master (90a8587) will decrease coverage by 1.53%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1027      +/-   ##
==========================================
- Coverage   60.27%   58.73%   -1.54%     
==========================================
  Files         169      172       +3     
  Lines       11415    11732     +317     
==========================================
+ Hits         6880     6891      +11     
- Misses       4535     4841     +306     

Impacted Files	Coverage Δ
boa/src/builtins/regexp/mod.rs	70.88% <100.00%> (+0.75%)	⬆️
boa/src/syntax/ast/node/operator/bin_op/mod.rs	52.32% <0.00%> (-14.35%)	⬇️
boa/src/syntax/ast/node/operator/unary_op/mod.rs	56.41% <0.00%> (-11.93%)	⬇️
boa/src/syntax/ast/node/statement_list/mod.rs	44.18% <0.00%> (-4.54%)	⬇️
boa/src/context.rs	61.56% <0.00%> (-4.13%)	⬇️
boa/src/lib.rs	88.46% <0.00%> (ø)
boa/src/profiler.rs	0.00% <0.00%> (ø)
boa/src/vm/mod.rs	0.00% <0.00%> (ø)
boa/src/vm/compilation.rs	0.00% <0.00%> (ø)
boa/src/vm/instructions.rs	0.00% <0.00%> (ø)
... and 1 more

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[Razican]

Looking good!

Test262 conformance changes:

Test result	master count	PR count	difference
Total	78,493	78,493	0
Passed	23,805	23,944	+139
Ignored	15,585	15,585	0
Failed	39,103	38,964	-139
Panics	362	147	-215
Conformance	30.33	30.50	+0.18%

[Razican]

Looks good, I would just remove the check for a Syntax error in the test, in order to avoid changing it when we fix regress.

[Razican]

I would just try to run it, without checking that it creates a Syntax error, since that will change in the future once we fix regress. If it panics, the test will fail, if it doesn't, it will pass.

[Razican]

This is linked to #817.