MC: Change MCAsmBackend::writeNopData() to take a raw_ostream instead of an MCObjectWriter. NFCI.

To make this work I needed to add an endianness field to MCAsmBackend
so that writeNopData() implementations know which endianness to use.

Part of PR37466.

Differential Revision: https://reviews.llvm.org/D47035

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332857 91177308-0d34-0410-b5e6-96231b3b80d8
25 files changed