[SLPVectorizer] Remove nullptr early-outs from Instruction::ShuffleVector getEntryCost

This code is only used by alternate opcodes so the InstructionsState has already confirmed that every Value is an Instruction, plus we use cast<Instruction> which will assert on failure.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336102 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed