feat(intl): implement Intl.DateTimeFormat.prototype.resolvedOptions()

[Lokesh0224]

Fixes the missing resolvedOptions() on DateTimeFormat — it was throwing
TypeError: not a callable function.

This PR implements the method following the
ECMA-402 11.3.2. Added the missing internal slots (numbering_system, hour_cycle, date_style, time_style) to the struct and populated them during construction.

LIMITATION
unicode-org/icu4x#5868
ICU4X does not yet expose the resolved calendar, numberingSystem, and hourCycle
from a constructed DateTimeFormatter, so ECMA-402 defaults are used as fallbacks.
Explicitly passed options are always reflected correctly.

Test262 resolvedOptions: 1/21 → 6/21

before resolvedOptoins():

after resolvedOptoins():

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	52,862	52,862	0
Passed	49,505	49,524	+19
Ignored	2,261	2,261	0
Failed	1,096	1,077	-19
Panics	0	0	0
Conformance	93.65%	93.69%	+0.04%

Fixed tests (28):

test/intl402/default-locale-is-canonicalized.js (previously Failed)
test/intl402/fallback-locales-are-supported.js (previously Failed)
test/intl402/constructors-taint-Object-prototype.js (previously Failed)
test/intl402/constructors-taint-Object-prototype-2.js (previously Failed)
test/intl402/DateTimeFormat/test-option-localeMatcher.js (previously Failed)
test/intl402/DateTimeFormat/constructor-options-toobject.js (previously Failed)
test/intl402/DateTimeFormat/test-option-formatMatcher.js (previously Failed)
test/intl402/DateTimeFormat/numbering-system-calendar-options.js (previously Failed)
test/intl402/DateTimeFormat/constructor-options-timeStyle-valid.js (previously Failed)
test/intl402/DateTimeFormat/constructor-options-dateStyle-valid.js (previously Failed)
test/intl402/DateTimeFormat/taint-Object-prototype-date-time-components.js (previously Failed)
test/intl402/DateTimeFormat/constructor-default-value.js (previously Failed)
test/intl402/DateTimeFormat/taint-Object-prototype-dayPeriod.js (previously Failed)
test/intl402/DateTimeFormat/taint-Object-prototype-fractionalSecondDigits.js (previously Failed)
test/intl402/DateTimeFormat/casing-numbering-system-calendar-options.js (previously Failed)
test/intl402/DateTimeFormat/canonicalize-calendar.js (previously Failed)
test/intl402/DateTimeFormat/taint-Object-prototype.js (previously Failed)
test/intl402/DateTimeFormat/ignore-invalid-unicode-ext-values.js (previously Failed)
test/intl402/DateTimeFormat/prototype/formatToParts/temporal-zoneddatetime-not-supported.js (previously Failed)
test/intl402/DateTimeFormat/prototype/formatRangeToParts/temporal-zoneddatetime-not-supported.js (previously Failed)
test/intl402/DateTimeFormat/prototype/formatRange/temporal-zoneddatetime-not-supported.js (previously Failed)
test/intl402/DateTimeFormat/prototype/format/temporal-zoneddatetime-not-supported.js (previously Failed)
test/intl402/DateTimeFormat/prototype/resolvedOptions/length.js (previously Failed)
test/intl402/DateTimeFormat/prototype/resolvedOptions/builtin.js (previously Failed)
test/intl402/DateTimeFormat/prototype/resolvedOptions/name.js (previously Failed)
test/intl402/DateTimeFormat/prototype/resolvedOptions/resolved-hour-cycle-unicode-extensions-and-options.js (previously Failed)
test/intl402/DateTimeFormat/prototype/resolvedOptions/prop-desc.js (previously Failed)
test/built-ins/RegExp/named-groups/non-unicode-property-names-valid.js (previously Ignored)

Broken tests (8):

test/built-ins/RegExp/prototype/exec/regexp-builtin-exec-v-u-flag.js (previously Passed)
test/built-ins/String/prototype/replace/regexp-prototype-replace-v-u-flag.js (previously Passed)
test/built-ins/String/prototype/matchAll/regexp-prototype-matchAll-v-u-flag.js (previously Passed)
test/built-ins/String/prototype/search/regexp-prototype-search-v-u-flag.js (previously Passed)
test/built-ins/String/prototype/search/regexp-prototype-search-v-flag.js (previously Passed)
test/built-ins/String/prototype/match/regexp-prototype-match-v-u-flag.js (previously Passed)
test/staging/sm/RegExp/unicode-raw.js (previously Passed)
test/staging/sm/RegExp/unicode-class-raw.js (previously Passed)

[codecov]

Codecov Report

❌ Patch coverage is 25.92593% with 60 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.18%. Comparing base (6ddc2b4) to head (c7059c2).
⚠️ Report is 701 commits behind head on main.

Files with missing lines	Patch %	Lines
...e/engine/src/builtins/intl/date_time_format/mod.rs	25.92%	60 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4753      +/-   ##
==========================================
+ Coverage   47.24%   57.18%   +9.94%     
==========================================
  Files         476      552      +76     
  Lines       46892    60572   +13680     
==========================================
+ Hits        22154    34638   +12484     
- Misses      24738    25934    +1196     

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[Lokesh0224]

@jedel1043, can you kindly go through the chat regarding // TODO: determine the correct way to verify the calendar algorithm data.