An crash when GetSpareOrNewBlock returns a contiguous address

[xinwei tang]

Hello, I found a case of crash, if NewArray in GetSpareOrNewBlock returns a contiguous address.

 If consecutive calls to HandleScope::Extend result in the first call's limit being exactly equal to the second call's block_start, then during HandleScope::DeleteExtensions, it will incorrectly judge that it is in a SealedHandleScope, leading to subsequent out-of-bounds access.