Fix/4614 textdecoder fatal

[Jayant-kernel]

This PR implements the fatal option for TextDecoder as per the specification.

Changes

• Updated TextDecoder to store the fatal flag.
• Updated TextDecoder constructor to parse the fatal option.
• Implemented strict decoding logic in utf8, utf16le, and utf16be decoders.
  • When fatal is true, invalid byte sequences now throw a TypeError instead of inserting the replacement character (U+FFFD).

Tests

• Added test cases in core/runtime/src/text/tests.rs verifying fatal: true behavior.
• Restored the roundtrip test case.

Fixes #4614

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	52,862	52,862	0
Passed	49,472	49,472	0
Ignored	2,249	2,249	0
Failed	1,141	1,141	0
Panics	0	0	0
Conformance	93.59%	93.59%	0.00%

[Jayant-kernel]

@ChALkeR
please review my pr when free.

[jedel1043]

This might have to be rebased against #4631, since it touches much of the same things and that PR is about to be merged.