Omit column info for CodeView by default

Clang tracks only start columns, not start-end ranges. CodeView allows for that, but the VS debugger doesn't handle anything less than a complete range well--it either highlights the wrong part of a statement or truncates source lines in the assembly view. It's better to have no column information at all.

So by default, we'll omit the column information for CodeView targeting Windows.

Since the column info is still useful for sanitizers, I've promoted -gcolumn-info (and -gno-column-info) to a CoreOption and added a couple tests to make sure that works for clang-cl.

Differential Revision: https://reviews.llvm.org/D23720

llvm-svn: 279765