Fix HTML comments in dynamic Function() and for-in initializer evaluation

[lahma]

Summary

• Fix CreateDynamicFunction wrapping to match spec (steps 16/29): line feeds after params and around body text ensure HTML-like comments (<!-- and -->) are correctly handled as line comments
• Implement AnnexB B.3.6: evaluate for-in loop variable initializer before enumeration (e.g., for (var a = ++effects in {}))
• Remove 6 test262 exclusions (5 HTML comment + 1 for-in initializer), all now passing

Details

CreateDynamicFunction (5 tests)

The spec requires specific line feed placement when constructing the source text:

sourceText = prefix + " anonymous(" + P + "\n) {\n" + bodyText + "\n}"

Previously, Jint only added newlines when the content contained /, which missed HTML-like comments (<!--, -->). Now always follows the spec layout, which correctly handles:

• Function("\n-->") — --> preceded by line feed is a valid HTML close comment
• Function("-->") — --> preceded by line feed (from wrapping) is valid
• Function("-->", "") — --> in params without preceding line feed correctly throws SyntaxError
• Function("<!--") — <!-- is always a valid HTML open comment

For-in initializer (1 test)

Per AnnexB B.3.6, for (var a = expr in obj) should evaluate the initializer before enumeration. The JintForInForOfStatement now detects when the LHS VariableDeclaration has a non-null Init and evaluates it in HeadEvaluation before the right-hand expression.

Test plan

• All 6 previously-excluded test262 tests now pass
• Full test262 suite: 0 failures, 95999 passed
• Jint.Tests: 0 failures, 2781 passed

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