Fix parse error throwing a TypeError, instead of SyntaxError

[iamsaquib8]

This Pull Request fixes/closes #741

It changes the following:

• eval method will throw syntaxError rather than typeError
• Adds a test for identifier

[codecov]

Codecov Report

Merging #748 into master will increase coverage by 0.08%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #748      +/-   ##
==========================================
+ Coverage   71.75%   71.84%   +0.08%     
==========================================
  Files         200      200              
  Lines       13983    13985       +2     
==========================================
+ Hits        10033    10047      +14     
+ Misses       3950     3938      -12     

Impacted Files	Coverage Δ
boa/src/context.rs	62.56% <100.00%> (+1.11%)	⬆️
boa/src/exec/tests.rs	100.00% <100.00%> (ø)
tester/src/exec.rs
tester/src/results.rs
tester/src/main.rs
tester/src/read.rs
boa_tester/src/main.rs	0.00% <0.00%> (ø)
boa_tester/src/results.rs	0.00% <0.00%> (ø)
boa_tester/src/read.rs	0.00% <0.00%> (ø)
boa_tester/src/exec.rs	0.00% <0.00%> (ø)
... and 3 more

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