Spellcheck Mixed Editable Long Text Crash

third_party/blink/web_tests/editing/spelling/spellcheck-mixed-editable-long-text-crash.html

150.0.7829.2188 B

Make TextCheckingParagraph.subrange() handles null position returned by endSentence() in multiple chunks case in SpellChecker::chunkAndMarkAllMisspellingsAndBadGrammar()

foo uneditable