feat(wintertc): implement structured clone for DataView

[MayankSharma-2812]

Closes #5530

Summary

Implements structured cloning serialization for DataView instances in boa_wintertc.

Previously, attempting to clone a DataView threw TypeError: Data views are not supported yet. even though deserialization (try_into_data_view) and storage (ValueStoreInner::DataView) were already implemented.

Changes

• Implemented clone_data_view in core/wintertc/src/store/from.rs to extract and serialize byte_offset, byte_length, and the underlying ArrayBuffer.
• Removed #[expect(unused)] from ValueStoreInner::DataView in core/wintertc/src/store/mod.rs.
• Added comprehensive unit tests in core/wintertc/src/clone/tests.rs verifying:
  • DataView byte offset and length preservation.
  • Value isolation between original and cloned buffers.
  • Object identity preservation for multiple DataViews sharing the same ArrayBuffer.

Verification

• cargo test -p boa_wintertc (56/56 passed)
• cargo clippy -p boa_wintertc -- -D warnings (0 warnings)
• cargo fmt -- --check (clean)

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	53,578	53,578	0
Passed	51,432	51,432	0
Ignored	1,648	1,648	0
Failed	498	498	0
Panics	0	0	0
Conformance	95.99%	95.99%	0.00%

Tested main commit: 69388e59f789ed0846a8d6aad1e4dc0c91b35816
Tested PR commit: edce572bf0570e29f4294d25a23488cfa0e9f7d0
Compare commits: 69388e5...edce572

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 62.98%. Comparing base (6ddc2b4) to head (edce572).
⚠️ Report is 1054 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #5531       +/-   ##
===========================================
+ Coverage   47.24%   62.98%   +15.74%     
===========================================
  Files         476      536       +60     
  Lines       46892    60297    +13405     
===========================================
+ Hits        22154    37980    +15826     
+ Misses      24738    22317     -2421     

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