Merging r322223:

Merging r322223:
------------------------------------------------------------------------
r322223 | matze | 2018-01-10 12:49:57 -0800 (Wed, 10 Jan 2018) | 5 lines

TargetLoweringBase: The ios simulator has no bzero function.

Make sure I really get back to the beahvior before my rewrite in r321035
which turned out not to be completely NFC as I changed the behavior for
the ios simulator environment.
------------------------------------------------------------------------

git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_60@322681 91177308-0d34-0410-b5e6-96231b3b80d8