fix(runtime): align borrowed typedarray prototype methods

[andrewtdiz]

Refs #4315

Summary

• Adds a regression fixture for %TypedArray%.prototype methods borrowed via .call, covering non-TypedArray TypeErrors and Uint8Array/Buffer receivers.
• Accepts Perry buffer-backed Uint8Array/Buffer receivers in TypedArray prototype thunks after the existing brand check, while still rejecting arrays and prototype-shaped objects.
• Implements the buffer-backed Uint8 method path for map, filter, slice, subarray, copyWithin, fill, reverse, sort, toReversed, toSorted, findIndex, findLastIndex, and set.
• Preserves Uint8Array vs Buffer result identity and omitted optional-arg defaults for copyWithin/fill.

Validation

• cargo check -p perry-runtime
• cargo fmt --all -- --check
• git diff --check
• ./scripts/check_file_size.sh
• Focused parity harness for globals/typedarray-branded-methods passed before the final expanded Buffer result-identity cases were added; the final expanded fixture was then manually compared against Node 26 and matched exactly.
• Manual Node 26/Perry comparisons matched for typedarray-callback-result-indexes, typedarray-own-properties, typedarray-prototype-accessor-throws, buffer/from/typed-array, buffer/typed-array/set, and buffer/copy-slice/subarray-shared.