fix(BinarySearch): add null key check to prevent NPE (fix #7356)#7357

DenizAltunkapan merged 2 commits intoTheAlgorithms:masterTheAlgorithms/Java:masterfrom

Senrian:fix/binary-search-null-key-handlingSenrian/Java:fix/binary-search-null-key-handlingCopy head branch name to clipboard