[MERGE #3845 @obastemur] CanonicalizeAccessor returns wrong results on cross thread
[MERGE #3845 @obastemur] CanonicalizeAccessor returns wrong results on cross thread

Merge pull request #3845 from obastemur:fix_ctt

`accessor` might be initialized under a different context hence `library->Undefined != accessor's->library->Undefined`

Recently added an Assert to IsUndefinedObject** checks. That assert helped revealing this issue.

See also https://github.com/Microsoft/ChakraCore/blame/master/lib/Runtime/Types/DictionaryTypeHandler.cpp#L2020

Microsoft/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore