MS ABI: Use '1' (instead of '0') relative scope discriminators

This changes the scope discriminator's behavior to start at '1' instead
of '0'.  Symbol table diffing, for ABI compatibility testing, kept
finding these as false positives.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@219075 91177308-0d34-0410-b5e6-96231b3b80d8
MS ABI: Make comment more accurate

The ABI for function-scope statics changed in VS "14", not MSVC 2013.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@219076 91177308-0d34-0410-b5e6-96231b3b80d8