fix: deep clone scope in FunctionEnvironment to prevent variable leak…

[yush-1018]

Fixes #5332

What's the bug?

When you call eval('var x = 1') inside a function, the variable x was
sticking around in the next call to that same function — even though it shouldn't.

function f(s) { return eval(s); }
f("eval('var x = 1;'); typeof x"); 
f("typeof x");                    

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	53,125	53,125	0
Passed	51,051	51,072	+21
Ignored	1,482	1,482	0
Failed	592	571	-21
Panics	0	1	+1
Conformance	96.10%	96.14%	+0.04%

Fixed tests (21):

test/staging/sm/Function/function-name-assignment.js (previously Failed)
test/staging/sm/strict/15.4.4.8.js (previously Failed)
test/staging/sm/strict/15.5.5.1.js (previously Failed)
test/staging/sm/strict/8.12.5.js (previously Failed)
test/staging/sm/strict/15.4.4.13.js (previously Failed)
test/staging/sm/strict/8.12.7.js (previously Failed)
test/staging/sm/strict/15.4.4.9.js (previously Failed)
test/staging/sm/strict/15.10.7.js (previously Failed)
test/staging/sm/strict/eval-variable-environment.js (previously Failed)
test/staging/sm/strict/15.4.4.12.js (previously Failed)
test/staging/sm/async-functions/await-in-arrow-parameters.js (previously Failed)
test/staging/sm/async-functions/await-in-parameters-of-async-func.js (previously Failed)
test/staging/sm/expressions/destructuring-array-default-simple.js (previously Failed)
test/staging/sm/expressions/destructuring-array-default-yield.js (previously Failed)
test/staging/sm/expressions/destructuring-array-default-function.js (previously Failed)
test/staging/sm/expressions/destructuring-array-default-function-nested.js (previously Failed)
test/staging/sm/expressions/destructuring-array-default-class.js (previously Failed)
test/staging/sm/expressions/short-circuit-compound-assignment.js (previously Failed)
test/staging/sm/expressions/destructuring-array-default-call.js (previously Failed)
test/staging/sm/PrivateName/lexical-presence.js (previously Failed)
test/staging/sm/extensions/for-loop-with-lexical-declaration-and-nested-function-statement.js (previously Failed)

New panics (1):

test/staging/sm/strict/strict-function-statements.js (previously Failed)

Tested main commit: 3ce87f0fa03c5c037fb667f7f21a4996abbbc714
Tested PR commit: 8ed8fe7d875a8add8737cb6b6d6361f494b149ee
Compare commits: 3ce87f0...8ed8fe7

[codecov]

Codecov Report

❌ Patch coverage is 33.33333% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.87%. Comparing base (6ddc2b4) to head (8ed8fe7).
⚠️ Report is 965 commits behind head on main.

Files with missing lines	Patch %	Lines
core/macros/src/module.rs	0.00%	6 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5339       +/-   ##
===========================================
+ Coverage   47.24%   59.87%   +12.63%     
===========================================
  Files         476      566       +90     
  Lines       46892    62932    +16040     
===========================================
+ Hits        22154    37682    +15528     
- Misses      24738    25250      +512     

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[yush-1018]

@jedel1043,

please review this PR.

[hansl]

Could you investigate the panic in test262?