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	51,049	51,070	+21
Ignored	1,482	1,482	0
Failed	594	573	-21
Panics	0	1	+1
Conformance	96.09%	96.13%	+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: da570fd74bb6cd5b0fc01363451eb710b7ab5a0c
Tested PR commit: 17074a695e1902c7ad376d235fc13546c70c17a5
Compare commits: da570fd...17074a6