TargetLoweringBase: Followup to r321035

I missed some prefixes and the fact that on AArch64 we use "bzero"
instead of "__bzero" as on X86 when doing my refactoring in r321035.

Improve tests for bzero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321046 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed